#include <bits/stdc++.h>
using namespace std;
void solve() {
  long long x, y, z, a, b, c;
  cin >> x >> y >> z >> a >> b >> c;
  if (a < x || (a - x + b) < y || (a - x + b - y + c) < z)
    cout << "NO";
  else
    cout << "YES";
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long t = 1;
  while (t--) solve();
}
