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