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

int main() {
  int a, b, c, A, B, C;
  char d;
  cin >> a >> d >> b >> d >> c;
  cin >> A >> d >> B >> d >> C;
  int v = 100 * a + 10 * b + c;
  int V = 100 * A + 10 * B + C;
  if (v >= V)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  return 0;
}