#include <bits/stdc++.h>
using namespace std;

int main() {
	unsigned long long a, b, c;
	cin >> a >> b >> c;
	if (c == a + b && c == a - b) {
		cout << "?"<<endl;
	} else if (c == a + b) {
		cout << "+"<<endl;
	} else if (c == a - b) {
		cout << "-"<<endl;
	} else  {
		cout << "!"<<endl;
	}
	return 0;
}

AT的题输出最好endl