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 fcout(d) cout << fixed << setprecision(d)
#define rep(i,n) for(int (i) = 0; (i) < (n); ++(i))
#define rep1(i,n) for(int (i) = 1; (i) <= (n); ++(i))
#define repU(i,bottom,ceiling) for(auto (i) = (bottom); (i) <= (ceiling); ++(i))
#define repD(i,ceiling,bottom) for(auto (i) = (ceiling); (i) >= (bottom); --(i))
#define repV(i,v) for(auto (i) = begin(v); (i) < end(v); ++(i))
#define all(v)  begin(v),end(v)
#define clr(v) fill(all(v),0)
#define l_bnd lower_bound
#define u_bnd upper_bound
#define puf push_front
#define pub push_back
#define pof pop_front
#define pob pop_back
#define mkp make_pair
#define mkt make_tuple
#define fir first
#define sec second
#define divceil(n,d) ((n)/(d) + ((n)%(d) > 0))
#define parity(a,b) (((a) & 1LL)^((b) & 1LL)^1LL)

typedef long long ll;
typedef unsigned long long ull;
typedef double db;

const pair<int,int> DIR[] = { {1,0},{0,1},{-1,0},{0,-1},{1,1},{-1,1},{-1,-1},{1,-1} };
const int INF_32 = -1 + (1 << 30);
const ll INF_64 = -1 + (1LL << 62);
const int MOD = (int)1e9 + 7;

ull next_subset(ull subset){
	ull tem = subset + (subset & -subset);
	ull btm = (~tem & subset) / (subset & -subset) >> 1;
	return btm | tem;
}


void solve(){
	
	
	int a,b; cin>>a>>b;
	if(a + b == 15) cout<<"+\n";
	else if(a * b == 15) cout<<"*\n";
	else cout<<"x\n";
	return;
}

void input(){
	
	
	
	return;
}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	
	input();
	solve();
	
	return 0;
}