using System;

public class Program

{

    public static void Main()

    {

        int a,b,c; char op;

        Console.WriteLine("a=");

        a = int.Parse(Console.ReadLine());

        Console.WriteLine("b=");

        b = int.Parse(Console.ReadLine());

        Console.WriteLine("enter any operation '+,-,*,/,%' ");

        op = char.Parse(Console.ReadLine());

        switch (op)

        {

            case '+':

            c = a + b;

                Console.WriteLine("c="+ c);

                break;

            case '*':

                c = a*b;

               Console.WriteLine("c=" + c);

                break;

            case '%':

            c = a%b;

                 Console.WriteLine("c=" + c);

                break;

            case '-':

            c = a - b;

            break;

            case '/':

                if (b < 0)

                {

                    Console.WriteLine("math eror");

                }

                else 

            {

                c = a/b;

                    Console.WriteLine("c=" + c);

                }

        break;

        }

    }

}