#include <bits/stdc++.h>

using namespace std;

int main(void) {
  int s[2];
  for (int i = 0; i < 2; i++) {
    int a, b, c;
    char ch;
    cin >> a >> ch >> b >> ch >> c;
    s[i] = a * 1000000 + b * 1000 + c;
  }

  cout << (s[1] < s[0] ? "YES" : "NO") << endl;

  return 0;
}