#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  vector<int> a(n, 0), b(n, 0);
  for (int i = 0; i < n; i++) cin >> a[i] >> b[i];
  int maxa = *max_element(a.begin(), a.end());
  sort(b.begin(), b.end(), greater<int>());
  long long ans = 0;
  for (int i = 0; i < n; i++) {
    if (maxa > b[i]) break;
    h -= b[i];
    ans++;
  }
  ans += ((long long)h + maxa - 1) / maxa;
  cout << ans << endl;
}
