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