#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h, k = 0, attack = 0, damage = 0;
  cin >> n >> h;
  vector<int> a(n, 0);
  vector<int> b(n, 0);
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    cin >> b[i];
  }
  sort(a.begin(), a.end());
  int a_max = a.back();
  int a_min = a.front();
  sort(b.begin(), b.end());
  int b_max = b.back();
  int b_min = b.front();
  for (int i = n - 1; i >= 0; i--) {
    if (b[i] > a_max) {
      attack++;
      damage += b[i];
    }
  }
  while (damage < h) {
    attack++;
    damage += a_max;
  }
  cout << attack << endl;
}
