#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, h;
  cin >> n >> h;
  vector<pair<long long, long long>> v;
  long long aa = 0;
  for (int i = 0; i < (int)(n); i++) {
    long long a, b;
    cin >> a >> b;
    v.push_back(make_pair(b, a));
    aa = max(aa, a);
  }
  sort(v.rbegin(), v.rend());
  long long ans = 0;
  for (int i = 0; i < (int)(n); i++) {
    if (aa > v[i].first) break;
    h -= v[i].first;
    ans++;
    if (h < 1) break;
  }
  ans += (h + aa - 1) / aa;
  cout << ans << endl;
  return 0;
}
