#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, h, c = 0, d = 0;
  cin >> n >> h;
  int a[n], b[n];
  for (int i = 0; i < n - 1; i++) {
    cin >> a[i] >> b[i];
    d = max(d, a[i]);
  }
  sort(b, b + n);
  for (int i = n - 1; i >= 0; i--) {
    if (b[i] < d) break;
    h -= b[i];
    c++;
    if (h <= 0) {
      cout << c;
      return 0;
    }
  }
  cout << c + (h - 1) / d + 1;
}
