/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner input = new Scanner(System.in);
        double num1, num2, result=0;    
        System.out.println("First number: ");
        num1 = input.nextDouble();
        System.out.println("Second number: ");
        num2 = input.nextDouble();
        String operator = "";
        while (operator.isEmpty()) {
          System.out.println("Enter Operator: ");
          operator = input.next();
          switch (operator) {
            case "+" : result = num1 + num2; break;
            case "-" : result = num1 - num2; break;
            case "*" : result = num1 * num2; break;
            case "/" : result = num1 / num2; break;
            default  : System.out.println("Invalid operator: " + operator);
                       operator = "";
           }
           System.out.println("Result is " + result);
        }
	}
}