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: Wrong Answer)

using System;

namespace atcoder
{
    class Program
    {
        static void Main(string[] args)
        {
            string a = Console.ReadLine();
            a = a.Replace(" ", "").Replace("　", "");
            int i = int.Parse(a);

            int i2 = (i % 10);
            int i1 = (i - i2) / 10;

            int a1 = i2 + i1;
            int a2 = i2 * i1;

            if(a1 == 15)
            {
                Console.WriteLine("+");
            }
            else if(a2 == 15)
            {
                Console.WriteLine("*");
            }
            else
            {
                Console.WriteLine("x");
            }

            Console.ReadLine();
            
        }

    }
}