#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, c;
  int x, y, z;
  cin >> x >> y >> z;
  cin >> a >> b >> c;
  int cnt = 0;
  if (a >= x) cnt++;
  if (a + b - x >= y) cnt++;
  if (a + b + c - x - y >= z) cnt++;
  if (cnt == 3)
    cout << "YES";
  else
    cout << "NO";
  return 0;
}
