#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h, ans, acnt, bcnt, a[100000], b[100000];
  cin >> n >> h;
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a, a + n);
  sort(b, b + n);
  ans = 0;
  acnt = n - 1;
  bcnt = n - 1;
  while (h > 0) {
    if (bcnt < 0 || a[n - 1] > b[bcnt]) {
      ans += (int)ceil((float)h / (float)a[acnt]);
      h = 0;
    } else {
      h -= b[bcnt];
      ans++;
      bcnt--;
    }
  }
  cout << ans << endl;
  return 0;
}
