#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  ll n, h;
  cin >> n >> h;
  vector<pair<int, bool>> ab(2 * n);
  for (int i = 0; i < n; i++) {
    cin >> ab[i * 2].first >> ab[i * 2 + 1].first;
    ab[i * 2].second = false;
    ab[i * 2 + 1].second = true;
  }
  sort(ab.rbegin(), ab.rend());
  int cnt = 0;
  ll dmg = 0;
  while (ab[cnt].second) {
    dmg += ab[cnt].first;
    cnt++;
    if (dmg > h) {
      cout << cnt << "\n";
      return 0;
    }
  }
  ll ta = ab[cnt].first;
  cnt += ((h - dmg + ta - 1) / ta);
  cout << cnt << "\n";
  return 0;
}
