#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using P = pair<int, int>;
int main() {
  ll n, h;
  cin >> n >> h;
  vector<ll> a(n), b(n);
  for (int i = 0; i < (n); ++i) cin >> a[i] >> b[i];
  ll mx = 0;
  for (int i = 0; i < (n); ++i) mx = max(mx, a[i]);
  ll ans = 0;
  for (int i = 0; i < (n); ++i) {
    if (b[i] >= mx) {
      ans++;
      h -= b[i];
    }
  }
  ans += (h + mx - 1) / mx;
  cout << ans << endl;
}
