#include <bits/stdc++.h>
const double PI =
    3.141592653589793238462643383279502884197169399375105820974944;
using namespace std;
void solve() {
  int x, y, z, a, b, c;
  cin >> x >> y >> z >> a >> b >> c;
  if (x > a) {
    cout << "NO"
         << "\n";
    return;
  }
  if (y > (a - x) + b) {
    cout << "NO"
         << "\n";
    return;
  }
  if (z > (a - x) + b - y + c) {
    cout << "NO"
         << "\n";
    return;
  }
  cout << "YES"
       << "\n";
}
int main() {
  bool testing = false;
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  if (testing) {
    freopen("test1.txt", "rt", stdin);
    int start = clock();
    solve();
    int end = clock();
    cout << "time: " << (end - start) / (double)(CLOCKS_PER_SEC)*1000
         << " milliseconds\n";
  } else {
    solve();
  }
}
