#include <bits/stdc++.h>
using namespace std;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n;
  long long h;
  cin >> n >> h;
  priority_queue<long long> pq;
  long long ma = 0;
  for (int i = 0; i < n; i++) {
    long long a, b;
    cin >> a >> b;
    ma = max(a, ma);
    pq.push(b);
  }
  long long ans = 0;
  while (h > 0 && !pq.empty()) {
    long long p = pq.top();
    pq.pop();
    if (ma < p) {
      ans++;
      h -= p;
    } else
      break;
  }
  ans += (h + ma - 1) / ma;
  cout << ans << endl;
  return 0;
}
