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