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 <bits/stdc++.h>

using namespace std;
#define rep(i, n) for(int i = 0 ; i < (int)(n) ; i++)
typedef long long ll;
typedef long double Double;

#ifndef INPUTS_DIR
#define INPUTS_DIR "./"
#endif


void solve(ll a, ll b) {
    if (a + b == 15) cout << "+" << endl;
    else if (a * b == 15) cout << "*" << endl;
    else cout << "x" << endl;
}


void main_(istream &cin) {
    ll b;
    ll a;
    cin >> a;
    cin >> b;
    solve(a, b);
}

int main() {
#ifdef INTELLIJ
    ifstream ifs(string(INPUTS_DIR) + "in_1.txt");
    if (ifs.is_open()) {
        main_(ifs);
        ifs.close();
    } else {
        cerr << "Error: no input." << endl;
    }
#else
    ios::sync_with_stdio(false);
    cin.tie(0);
    main_(cin);
#endif
}