#include <bits/stdc++.h>
using namespace std;
int main(void) {
  long long n, h;
  cin >> n >> h;
  long long a[n], b[n];
  long long sumb = 0;
  long long maa = 0, mib = 100000000000;
  for (long long i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    sumb += b[i];
    maa = max(maa, a[i]);
    mib = min(mib, b[i]);
  }
  long long ans = 0;
  for (long long i = 0; i < n; i++) {
    if (b[i] > maa) {
      ans++;
      h -= b[i];
    }
  }
  if (h > 0) {
    ans += h / maa;
    if (h % maa != 0) ans++;
  }
  cout << ans << endl;
  return 0;
}
