#include <bits/stdc++.h>
using namespace std;
int main(int argc, char *argv[]) {
  int N, H;
  cin >> N >> H;
  long amax = 0;
  list<long> b;
  for (int i = 0; i < N; i++) {
    int ai, bi;
    cin >> ai >> bi;
    b.push_back(bi);
    if (amax < ai) amax = ai;
  }
  b.sort(greater<long>());
  int atk = 0;
  for (long bi : b) {
    if (bi < amax) break;
    if (H <= 0) break;
    H -= bi;
    atk++;
  }
  atk += (H + amax - 1) / amax;
  cout << atk << endl;
  return 0;
}
