#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  long long h;
  cin >> n >> h;
  long long a[114514], b = 0;
  for (int i = 0; i < n; i++) {
    long long k;
    cin >> k >> a[i];
    b = max(b, k);
  }
  sort(a, a + n);
  int ans = 0;
  for (int i = n - 1; a[i] >= b; i--) {
    h -= a[i];
    ans++;
    if (h <= 0) goto heaven;
  }
  while (h > 0) {
    ans++;
    h -= b;
  }
heaven:
  cout << ans << endl;
  return 0;
}
