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: Accepted)

using System;
using System.Linq;
namespace ConsoleTest {
  class Program {
    static void Main(string[] args) {
      int[] a = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
      if (a[0] + a[1] == 15) {
        Console.WriteLine("+");
      } else if (a[0] * a[1] == 15) {
        Console.WriteLine("*");
      } else {
        Console.WriteLine("x");
      }
    }
  }
}