#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int x, y, z, a, b, c;
  cin >> x >> y >> z >> a >> b >> c;
  if (a >= x) {
    a = a - x;
    if ((b + a) >= y) {
      long long int e = (b + a) - y;
      if (e + c >= z) {
        cout << "YES" << endl;
      } else {
        cout << "NO" << endl;
      }
    } else {
      cout << "NO" << endl;
    }
  } else {
    cout << "NO" << endl;
  }
}
