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