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