#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  long h;
  cin >> h;
  pair<int, int> ab[2 * n];
  int a, b;
  for (int i = 0; i < (int)(n); i++) {
    cin >> a >> b;
    ab[2 * i] = {a, 0};
    ab[2 * i + 1] = {b, 1};
  }
  sort(ab, ab + 2 * n);
  reverse(ab, ab + 2 * n);
  long cnt, res = h;
  for (int i = 0; i < (int)(2 * n); i++) {
    if (ab[i].second == 1) {
      cnt++;
      res -= ab[i].first;
    } else {
      cnt += ceil(res / ab[i].first);
      break;
    }
  }
  cout << cnt;
}
