include

using namespace std;

int main() {

int a, b, c, d, S;
cin >> a >> b >> c >> d >> S;

if (a + b == S || a + c == S || a + d == S|| b + c == S || b + d == S || c + d == S) {
	cout << "1";
} else {
	cout << "-1";
}

return 0;

}