#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  ll n, hp;
  cin >> n >> hp;
  vector<ll> swing(n), throws(n);
  ll m = 0;
  for (int i = 0; i < n; i++) {
    cin >> swing[i] >> throws[i];
    m = max(m, swing[i]);
  }
  ll cnt = 0;
  ll sum = 0;
  for (int i = 0; i < n; i++) {
    if (m < throws[i]) {
      cnt++;
      sum += throws[i];
    }
  }
  ll ans = 0;
  ll rem = hp - sum;
  ans += rem / m;
  if (rem % m) ans++;
  cout << cnt + ans << endl;
}
