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.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Numerics; 

class _Class
{
  void _Do()
  {
    var ab = Split.ints();
    var a = ab[0];
    var b = ab[1];

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


  //
  static void Main(string[] args)
  {
    _(args);
    new _Class()._Do();
  }

  [Conditional("DEBUG")]
  static void _(string[] args)
  {
    if (args.Length != 0 && File.Exists(args[0]))
      Console.SetIn(new StreamReader(args[0]));
    else
      Console.Error.WriteLine("in");
  }
}

static class Split
{


  // 1
  public static string[] strings()
  {
    return Console.ReadLine().Split();
  }


  // [2.1] -2,147,483,648 ~ +2,147,483,647
  public static int[] ints()
  {
    var _s = Console.ReadLine().Split();

    var x = new int[_s.Length];
    for (var i = 0; i < _s.Length; i++)
      x[i] = int.Parse(_s[i]);

    return x;
  }

  // [2.2] 
  // -9,223,372,036,854,775,808 ~ 
  // +9,223,372,036,854,775,807
  public static long[] longs()
  {
    var _s = Console.ReadLine().Split();

    var x = new long[_s.Length];
    for (var i = 0; i < _s.Length; i++)
      x[i] = long.Parse(_s[i]);

    return x;
  }

  public static double[] doubles()
  {
    var _s = Console.ReadLine().Split();

    var x = new double[_s.Length];
    for (var i = 0; i < _s.Length; i++)
      x[i] = double.Parse(_s[i]);

    return x;
  }

  public static BigInteger[] bigs()
  {
    var _s = Console.ReadLine().Split();

    var x = new BigInteger[_s.Length];
    for (var i = 0; i < _s.Length; i++)
      x[i] = BigInteger.Parse(_s[i]);

    return x;
  }
}