#include <bits/stdc++.h>
int main(void) {
  unsigned int n, a[200000], b[200000];
  unsigned int max, i, count = 0;
  int h;
  scanf("%d %d", &n, &h);
  max = a[0];
  for (i = 0; i < n; i++) {
    scanf("%d %d", &a[i], &b[i]);
  }
  for (i = 0; i < n; i++) {
    if (max < a[i]) max = a[i];
  }
  for (i = 0; i < n; i++) {
    if (max <= b[i]) {
      h -= b[i];
      count++;
    }
  }
  while (h > 0) {
    h -= max;
    count++;
  }
  printf("%d", count);
  return 0;
}
