#include <bits/stdc++.h>
using namespace std;
const int INF = 1001001001;
int main() {
  long long n, h;
  cin >> n >> h;
  vector<long long> b(n);
  long long amax = 0;
  for (int i = 0; i < n; ++i) {
    long long a1, b1;
    cin >> a1 >> b1;
    b[i] = b1;
    amax = max(a1, amax);
  }
  sort(b.begin(), b.end());
  long long idx = lower_bound(b.begin(), b.end(), amax) - b.begin();
  long long now = n - 1;
  long long cnt = 0;
  while (h > 0) {
    if (now < idx) break;
    h -= b[now];
    now--;
    cnt++;
  }
  if (h > 0) {
    cnt += (h + 1) / amax;
  }
  cout << cnt;
}
