Problem:
Score : 100 points

Problem Statement

You are given two integers a and b.
Determine if a+b=15 or a\times b=15 or neither holds.

Note that a+b=15 and a\times b=15 do not hold at the same time.

Constraints

1 \leq a,b \leq 15

All values in input are integers.

Input

Input is given from Standard Input in the following format:

a b

Output

If a+b=15, print +;
if a\times b=15, print *;
if neither holds, print x.

Sample Input 1

4 11

Sample Output 1

+

4+11=15.

Sample Input 2

3 5

Sample Output 2

*

3\times 5=15.

Sample Input 3

1 1

Sample Output 3

x

1+1=2 and 1\times 1=1, neither of which is 15.

Solution in C# (Mono 4.6.2.0) (judge verdict: Runtime Error)

using System;

namespace problem_1
{
    class Program
    {
        static void Main(string[] args)
        {
            int a, b;

            a = Convert.ToInt32(Console.ReadLine());
            b = Convert.ToInt32(Console.ReadLine());

            if (a+b == 15)
            {
                Console.WriteLine("+");
            }
            else if (a * b == 15)
            {
                Console.WriteLine("*");
            }
            else
            {
                Console.WriteLine("X");
            }
            Console.ReadLine();
        }
    }
}