/*
 * Copyright (c) 2008, Manuel Mausz <manuel at mausz.at>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the copyright holders nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

import java.io.InputStream;
import java.util.HashMap;
import java.util.Scanner;
import java.lang.Class;
import java.lang.Boolean;
import java.lang.reflect.*;
import java.util.InputMismatchException;
import java.lang.NoSuchMethodException;


/**
 * CalcOperator encapsulate an Operator
 * NOTE: This class isn't public due to EPROG limitations.
 * EPROG doesn't allow shipping files not specified
 *
 * @version 1.0
 * @author  Manuel Mausz (manuel at mausz.at)
 * @author  http://manuel.mausz.at/
 */
class CalcOperator
{
  private String op;

  /**
   * Constructor
   *
   * @param value init value
   */
  CalcOperator(String op)
  {
    this.op = op;
  }

  /**
   * @return encapsulated operator
   */
  public String get()
  {
    return op;
  }

  /**
   * Indicates whether some other object is "equal to" this one
   *
   * @param obj the reference object with which to compare
   * @return true if this object is the same as the obj argument; false otherwise
   */
  public boolean equals(Object op2)
  {
    if (op2 == null)
      return false;
    else if (op2 instanceof CalcOperator)
      return this.op.equals(((CalcOperator) op2).get());
    else
      return false;
  }

  /**
   * Returns a hash code value for the object
   *
   * @return string
   */
  public int hashCode()
  {
    return op.hashCode();
  }

  /**
   * Converts instance to string
   *
   * @return string
   */
  public String toString()
  {
    return op;
  }
}


/**
 * Abstract for CalcValue
 *
 * @version 1.0
 * @author  Manuel Mausz (manuel at mausz.at)
 * @author  http://manuel.mausz.at/
 */
abstract class CalcValue
{
  protected static HashMap<CalcOperator, String> operators = new HashMap<CalcOperator, String>();

  /**
   * Assigns an operator to a method
   *
   * @param op operator
   * @param func method name
   */
  protected void addOp(CalcOperator op, String func)
  {
    operators.put(op, func);
  }

  /**
   * Checks if instance has an method assigned to operater
   *
   * @param op operator
   * @return boolean
   */
  public boolean isSupported(CalcOperator op)
  {
    return operators.containsKey(op);
  }

  /**
   * Invokes the method assigned to operator
   * passes value as argument
   *
   * @param value argument passed to the invoked method
   * @param op operator
   * @return object return by invoked method
   * @throws NoSuchMethodException
   * @throws InvocationTargetException
   */
  public Object calc(CalcValue value, CalcOperator op)
    throws NoSuchMethodException, InvocationTargetException
  {
    Object ret = null;

    String methodname = operators.get(op);
    if (methodname == null)
      throw new NoSuchMethodException("Method for operator '" + op.get() + "' not found");

    try
    {
      Method method = this.getClass().getMethod(methodname, new Class[] { value.getClass() });
      ret = method.invoke(this, new Object[] { value } );
    }
    catch(IllegalAccessException e)
    {
      throw new NoSuchMethodException(e.getMessage());
    }

    return ret;
  }
}


/**
 * CalcInteger encapsulate an Integer value
 * NOTE: This class isn't public due to EPROG limitations.
 * EPROG doesn't allow shipping files not specified
 *
 * @version 1.0
 * @author  Manuel Mausz (manuel at mausz.at)
 * @author  http://manuel.mausz.at/
 */
class CalcInteger extends CalcValue
{
  private int value;

  /**
   * Constructor
   *
   * @param value init value
   */
  CalcInteger(int value)
  {
    addOps();
    this.value = value;
  }

  /**
   * Add supported operations
   */
  private void addOps()
  {
    addOp(new CalcOperator("+"), "add");
    addOp(new CalcOperator("-"), "sub");
    addOp(new CalcOperator("*"), "mul");
    addOp(new CalcOperator("/"), "div");
  }

  /**
   * @return encapsulated integer
   */
  public int get()
  {
    return value;
  }

  /**
   * Converts instance to string
   *
   * @return string
   */
  public String toString()
  {
    return Integer.toString(value);
  }

  /**
   * Addition
   *
   * @param val
   * @return new CalcInteger instance
   */
  public CalcInteger add(CalcInteger val)
  {
    return new CalcInteger(value + val.get());
  }

  /**
   * Subtraction
   *
   * @param val
   * @return new CalcInteger instance
   */
  public CalcInteger sub(CalcInteger val)
  {
    return new CalcInteger(value - val.get());
  }

  /**
   * Multiplication
   *
   * @param val
   * @return new CalcInteger instance
   */
  public CalcInteger mul(CalcInteger val)
  {
    return new CalcInteger(value * val.get());
  }

  /**
   * Division
   *
   * @param val
   * @return new CalcInteger instance
   */
  public CalcInteger div(CalcInteger val)
  {
    return new CalcInteger(value / val.get());
  }
}


/**
 * Calculator
 *
 * @version 1.0
 * @author  Manuel Mausz (manuel at mausz.at)
 * @author  http://manuel.mausz.at/
 */
public class Calculator
{
  private static CalcInteger val1;
  private static CalcInteger val2;
  private static CalcOperator op;

  /**
   * read values and operator from src
   * only allow syntax: "int int op"
   *
   * @param src input stream
   * @return boolean always true
   * @throws InputMismatchException
   * @throws NoSuchMethodException
   * @throws InvocationTargetException
   */
  public static boolean parse(InputStream src)
    throws InputMismatchException, NoSuchMethodException, InvocationTargetException
  {
    /* get first line only */
    Scanner scanner = new Scanner(System.in);
    String line1 = scanner.nextLine();
    scanner.close();

    /* parse first line */
    scanner = new Scanner(line1);

    if (!scanner.hasNextInt())
      throw new InputMismatchException("Invalid first param. No integer");
    val1 = new CalcInteger(scanner.nextInt());

    if (!scanner.hasNextInt())
      throw new InputMismatchException("Invalid second param. No integer");
    val2 = new CalcInteger(scanner.nextInt());

    if (!scanner.hasNext())
      throw new InputMismatchException("Invalid operator");
    op = new CalcOperator(scanner.next());

    /* check for additional chars */
    if (scanner.hasNext())
      throw new InputMismatchException("Invalid chars at the end of line");

    scanner.close();

    return true;
  }

  /**
   * main method
   *
   * @param args not used
   */
  public static void main(String[] args)
  {
    try
    {
      /* parse stdin */
      parse(System.in);

      /* do calculation */
      Object newval = val1.calc(val2, op);
      if (!(newval instanceof CalcInteger))
        throw new InputMismatchException("Unrecognized classtype returned from operation");

      /* print result to stdout */
      System.out.println(((CalcInteger) newval).get());
    }
    catch(Throwable e)
    {
      System.out.println("FALSCHE EINGABE");
    }
  }
}