#include <bits/stdc++.h>
int main() {
  int x, y, z, a, b, c;
  scanf("%d %d %d %d %d %d", &x, &y, &z, &a, &b, &c);
  if (a >= x && (a - x + b) >= y && (a - x + b - y + c) >= z)
    printf("YES");
  else
    printf("NO");
  return 0;
}
