#include <bits/stdc++.h>
using namespace std;
long long n, h;
long long a[114514], b[114514];
signed main() {
  cin >> n >> h;
  for (long long i = 0; i < n; i++) cin >> a[i] >> b[i];
  sort(a, a + n);
  long long cnt = 0, memo = 0;
  for (long long i = 0; i < n; i++) {
    if (b[i] <= a[n - 1]) continue;
    if (cnt >= h) break;
    cnt += b[i];
    memo++;
  }
  if (cnt >= h)
    cout << memo << endl;
  else
    cout << ((h - cnt) - 1) / a[n - 1] + 1 + memo << endl;
  getchar();
  getchar();
  return 0;
}
