#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, h, a, b, c = 0, cnt = 0;
  vector<long long int> vec;
  long long int i, j, k;
  cin >> n >> h;
  for (i = 0; i < (n); i++) {
    cin >> a >> b;
    vec.push_back(b);
    c = max(c, a);
  }
  sort(vec.begin(), vec.end());
  for (i = 0; i < (n); i++) {
    if (vec[n - 1 - i] > c) {
      h -= vec[n - 1 - i];
      cnt++;
      if (h <= 0) {
        break;
      }
    } else {
      break;
    }
  }
  cnt += ceil((double)h / (double)c);
  cout << cnt << endl;
}
