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