#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, h;
  cin >> n >> h;
  vector<pair<long long, long long>> vec;
  for (long long i = 0; i < n; i++) {
    long long a, b;
    cin >> a >> b;
    vec.push_back(make_pair(a, b));
  }
  long long biggest = 0;
  for (long long i = 0; i < n; i++) {
    if (biggest < vec[i].first) biggest = vec[i].first;
  }
  long long count = 0;
  for (long long i = 0; i < n; i++) {
    if (biggest < vec[i].second) {
      h -= vec[i].second;
      count++;
      if (h <= 0) {
        cout << count << endl;
        return 0;
      }
    }
  }
  if (h % biggest == 0)
    cout << count + h / biggest << endl;
  else
    cout << count + h / biggest + 1 << endl;
  return 0;
}
