#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, H;
  cin >> N >> H;
  int a, b[N];
  int a_max = 0;
  for (int i = 0; i < N; i++) {
    cin >> a;
    a_max = max(a, a_max);
    cin >> b[i];
  }
  int max_turn = 0;
  sort(b, b + N);
  for (int i = N - 1; i >= 0; i++) {
    if (H <= 0 || b[i] < a_max) break;
    max_turn++;
    H -= b[i];
  }
  if (H > 0) max_turn += (H + a_max - 1) / a_max;
  cout << max_turn << endl;
  return 0;
}
