#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, H;
  cin >> N >> H;
  int a[N];
  int b[N];
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a, a + N, greater<int>());
  sort(b, b + N, greater<int>());
  int i = 0;
  int cnt = 0;
  while (b[i] >= a[0] && i < N) {
    H -= b[i];
    cnt++;
    i++;
  }
  cout << cnt + (H + (a[0] - 1)) / a[0] << endl;
}
