#include <bits/stdc++.h>
using namespace std;
const double EPS = 1e-9;
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  long long n, h;
  cin >> n >> h;
  vector<pair<long long, long long> > a(n);
  for (long long i = (0); i < ((n)); ++i) cin >> a[i].second >> a[i].first;
  sort(a.begin(), a.end());
  long long ans = 0, mx = 0;
  for (long long i = (0); i < ((n)); ++i) {
    mx = max(mx, a[i].second);
    h -= a[i].first;
    ans++;
    if (h <= 0) break;
  }
  if (h > 0) ans += h / mx + (h % mx > 0);
  cout << ans << endl;
  return 0;
}
