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)

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<sstream>
#include<vector>
#include<algorithm>
#include<string.h>
#include<set>
#include<fstream>
#include<map>
#include<string>
#include <stdio.h>
#include<bitset>
#include<queue>
#include<iomanip>
#include<cmath>
#include<stack>
#include<climits>
#include<functional>

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<ll>vl;
typedef vector<int>vi;
typedef vector<bool>vb;
typedef vector<double>vd;
typedef vector<char>vc;
typedef vector<string>vs;
#define MP make_pair
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define EPS 1e-9
#define PI 3.14159265359
const ll mod = 1000000007;
const ll OO = (ll)1e9;
const int dx[] = { 0, 1, 0, -1, 1, -1, 1, -1 };
const int dy[] = { 1, 0, -1, 0, 1, -1, -1, 1 };
ll gcd(ll a, ll b){ if (b == 0){ return a; }return gcd(b, a % b); }
ll fast_power(ll base, ll power){
	if (power == 0)
		return 1;
	if (power == 1)
		return (base % mod);
	if (power % 2 == 0)
		return (fast_power(((base*base) % mod), power / 2LL) % mod);
	else return ((base*fast_power(((base*base) % mod) % mod, power / 2LL)) % mod);
}
//#pragma warning (disable : 4996)
void Qalbaz()
{

	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	cout << fixed << setprecision(2);
}

int main(){

	Qalbaz();

	int a, b;
	cin >> a >> b;
	if (a + b == 15)
		cout << '+';
	else if (a * b == 15)
		cout << '*';
	else
		cout << 'x';

	return 0;
}