#include <bits/stdc++.h>
using namespace std;
int main() {
  int x, y, z, a, b, c, q;
  cin >> x >> y >> z >> a >> b >> c;
  q = x;
  x -= a;
  a -= q;
  if (x > 0) {
    cout << "NO";
    return 0;
  }
  if (a + b < y) {
    cout << "NO";
    return 0;
  }
  q = a + b - y;
  if (q + c < z) {
    cout << "NO";
    return 0;
  }
  cout << "YES";
}
