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