#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  scanf("%d%d", &n, &h);
  priority_queue<pair<long long, int>> pq;
  for (int i = 0; i < n; i++) {
    long long a, b;
    scanf("%lld%lld", &a, &b);
    pq.emplace(a, 0);
    pq.emplace(b, 1);
  }
  long long ans = 0;
  while (!pq.empty()) {
    pair<long long, int> get = pq.top();
    pq.pop();
    if (!get.second) {
      ans += (h + get.first - 1) / get.first;
      break;
    } else {
      ans++;
      h -= get.first;
    }
  }
  printf("%lld\n", ans);
  return 0;
}
