#include <iostream>
using namespace std;
int main() {
	int A[3];
	int a;
	int B[3];
	int b;
	char token;
	cin >> A[0] >> token >> A[1] >> token >> A[2];
	cin >> B[0] >> token >> B[1] >> token >> B[2];
	a = A[0] * 10000 + A[1] * 100 + A[2];
	b = B[0] * 10000 + B[1] * 100 + B[2];
	if (a < b) { cout << "NO" << endl; }
	else { cout << "YES" << endl; }
	return 0;
}