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