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