#include <bits/stdc++.h>
using namespace std;
signed main() {
  int64_t N, H, maxa = -123, ans = 0;
  cin >> N >> H;
  vector<int64_t> b(N);
  for (int64_t i = (0); i < (N); i++) {
    int64_t a;
    cin >> a >> b[i];
    maxa = max(maxa, a);
  }
  sort(begin(b), end(b));
  for (int64_t i = N - 1; H > 0 && i >= 0 && b[i] > maxa; i--) {
    H -= b[i];
    ans++;
  }
  ans += (H + maxa - 1) / maxa;
  cout << ans << endl;
  return 0;
}
