#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  long hp, r = 0;
  cin >> n >> hp;
  vector<long> 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 lastI;
  for (int i = n - 1; i >= 0; i--) {
    if (b[i] < a[n - 1]) {
      lastI = i + 1;
      break;
    }
  }
  int j = n - 1;
  while (hp > 0) {
    hp -= b[j];
    r++;
    if (j == lastI) {
      if (hp <= 0) break;
      r += hp / a[n - 1];
      if (hp % a[n - 1] != 0) r++;
      hp -= (hp / a[n - 1] + 1) * a[n - 1];
    }
    j--;
  }
  cout << r << endl;
}
