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