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