#include <bits/stdc++.h>
void quicksort(int a[], int s, int t) {
  if (s < t) {
    int i = s, j = t, p = a[(s + t) / 2];
    while (1) {
      while (a[i] > p) i++;
      while (p > a[j]) j--;
      if (i >= j) break;
      a[i] ^= a[j] ^= a[i] ^= a[j];
      i++;
      j--;
    }
    quicksort(a, s, i - 1);
    quicksort(a, j + 1, t);
  }
}
int main() {
  int n, h, a[100000], b[100000], c = 0, i = 0;
  scanf("%d%d", &n, &h);
  for (i = 0; i < n; i++) scanf("%d%d", &a[i], &b[i]);
  quicksort(a, 0, n - 1);
  quicksort(b, 0, n - 1);
  while (b[i] > a[0] && c < h) {
    c += a[i];
    i++;
  }
  if (c < h) i += (h - c + a[0] - 1) % a[0];
  printf("%d", i);
}
