#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7;
int main() {
  int n;
  long long h;
  cin >> n >> h;
  vector<pair<long long, long long>> s(n);
  long long a, b;
  for (int i = 0; i < n; ++i) {
    cin >> a >> b;
    s[i] = make_pair(a, b);
  }
  sort(s.begin(), s.end(), greater<pair<long long, long long>>());
  long long attack = s[0].first;
  long long ans = 0;
  for (int i = 0; i < n; ++i) {
    if (s[i].second > attack) {
      h -= s[i].second;
      ans++;
    }
    if (h <= 0) {
      cout << ans << endl;
      return 0;
    }
  }
  if (h > 0) ans += (h + attack - 1) / attack;
  cout << ans << endl;
}
