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 <utility>
#include <vector>
#include <iostream>
#include <algorithm>
#include <set>
#define REP(i,n) for(int i=0;i<n;i++)
typedef unsigned long ul;
typedef unsigned long long ull;
typedef long long ll;
using namespace std;
int gcd(int a,int b){return b?gcd(b,a%b):a;}
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};

int main() {
	cin.tie(0);
   	ios::sync_with_stdio(false);
    int a, b;
    cin >> a >> b;
    string ans;
    if(a+b == 15){
        ans = '+';
    }else if (a*b == 15){
        ans = '*';
    }else{
        ans = 'x';
    }

    cout << ans << endl;
    return 0;
}