#include <bits/stdc++.h>
using namespace std;
struct node {
  int a, b;
} val[100001];
bool comp(struct node &A, struct node &B) { return A.b < B.b; }
int main(int argc, const char *argv[]) {
  int n, h;
  scanf("%d %d", &n, &h);
  int ms = 0, mi = 0, x = 0;
  for (int i = 0, t1, t2; i < n; i++) {
    scanf("%d %d", &t1, &t2);
    val[i].a = t1;
    val[i].b = t2;
    if (ms < t1) {
      ms = t1;
      mi = i;
      x = t2;
    }
  }
  int ans = 0;
  for (int i = 0; i < n; i++) {
    if (ms < val[i].b && i != mi) {
      h = h - val[i].b;
      ans++;
    }
    if (h <= 0) {
      printf("%d\n", ans);
      return 0;
    }
  }
  if (h - x > 0) {
    if ((h - x) % ms != 0) ans++;
    printf("%d\n", ans + (h - x) / ms + 1);
  } else {
    printf("%d\n", ans + 1);
  }
  return 0;
}
