#include <bits/stdc++.h>
using namespace std;
int n, h, ans;
int a, b[100005];
int main() {
  scanf("%d%d", &n, &h);
  for (int i = 0; i < n; i++) {
    int t;
    scanf("%d%d", &t, &b[i]);
    a = max(a, t);
  }
  sort(b, b + n, greater<int>());
  for (int i = 0; i < n; i++) {
    if (b[i] <= a) {
      break;
    }
    if (h == 0) {
      break;
    }
    h -= b[i];
    ans++;
  }
  h = max(h, 0);
  ans += (h + a - 1) / a;
  printf("%d", ans);
  return 0;
}
