#include <iostream>

using namespace std;

int main()
{
    int a, b, c, d;
    cin >> a >> b >> c >> d;

    int r = a + b + c;
    int kolku = 0;
    if(r % 2 == 0) {
        kolku += 1;
    }
    r = a + b + d;
    if(r % 2 == 0) {
        kolku += 1;
    }

    r = a + c + d;
    if(r % 2 == 0) {
        kolku += 1;
    }
    r = b + c + d;
    if(r % 2 == 0) {
        kolku += 1;
    }

    if(kolku == 1) {
        cout << "+" << endl;
    }
    else if(kolku > 1) {
        cout << "?" << endl;
    }
    else {
        cout << "-" << endl;
    }
    return 0;
}