#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int x, y, z;
  cin >> x >> y >> z;
  int a, b, c;
  cin >> a >> b >> c;
  bool c1 = a >= x;
  bool c2 = a - x + b >= y;
  bool c3 = a + b - x - y + c >= z;
  if (c1 and c2 and c3) {
    cout << "YES" << endl;
  } else {
    cout << "NO" << endl;
  }
  return 0;
}
