#include <bits/stdc++.h>
using namespace std;
long long a[100001] = {};
long long b[100001] = {};
int main() {
  long long N, H;
  cin >> N >> H;
  long long maxV = 0;
  long long cnt = 0;
  for (long long i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
    maxV = max(maxV, a[i]);
  }
  for (long long i = 0; i < N; i++) {
    if (maxV < b[i]) {
      H -= b[i];
      cnt++;
      if (H <= 0) {
        cout << cnt << endl;
        return 0;
      }
    }
  }
  cout << cnt + ((H - 1) / maxV) + 1 << endl;
  return 0;
}
