#include <bits/stdc++.h>
using namespace std;
int main(int argc, char const *argv[]) {
  int x, y, z;
  cin >> x >> y >> z;
  int a, b, c;
  cin >> a >> b >> c;
  if (a < x) {
    cout << "NO" << endl;
    return 0;
  }
  if (a - x + b < y) {
    cout << "NO" << endl;
    return 0;
  }
  if (a + b + c - x - y < z) {
    cout << "NO" << endl;
    return 0;
  }
  cout << "YES" << endl;
  return 0;
}
