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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <string>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
#include <set>
#include <list>
#include <queue>
#define INF 1<<19
const int MOD = 1000000007;
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
using namespace std;
typedef long long ll;
typedef pair<int,int> P;
 
int main(){
    int a,b;
    cin >> a >> b;
    if(a+b == 15){
        cout << '+' << endl;
    }else if(a * b == 15){
        cout << '*' << endl;
    }else{
        cout << 'x' << endl;
    }
    return 0;
}