#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  vector<int> a(n), b(n);
  int ma = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    ma = max(ma, a[i]);
  }
  int ans = 0;
  bool ok = false;
  for (int i = 0; i < n; i++) {
    if (ma < b[i]) {
      ans++;
      h -= b[i];
    }
    if (h < 0) {
      ok = true;
      break;
    }
  }
  if (!ok) {
    ans += (h + ma - 1) / ma;
  }
  cout << ans << endl;
}
