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