#include <bits/stdc++.h>
using namespace std;
#define rep(i, m, n) for (int i = m; i < n; ++i)

int main() {
  int N, H;
  cin >> N >> H;
  vector<int> a(N), b(N);
  rep(i, 0, N) cin >> a[i] >> b[i];
  int mx = *max_element(a.begin(), a.end());
  sort(b.begin(), b.end(), greater<int>());
  int ans = 0;
  rep(i, 0, N) {
    if(b[i] < mx || H <= 0) break;
    ans++;
    H -= b[i];
  }
  if(H > 0) ans += (H + mx - 1) / mx;
  cout << ans << endl;
  return 0;
}
