#include <bits/stdc++.h>
using namespace std;
signed main() {
  int64_t n, h;
  cin >> n >> h;
  priority_queue<int64_t> q;
  int64_t s = 0;
  for (int64_t i = 0; i < (int64_t)(n); i++) {
    int64_t a, b;
    cin >> a >> b;
    q.push(b);
    s = max(s, a);
  }
  int64_t ans = 0;
  while (!q.empty() && s < q.top() && h > 0) {
    h -= q.top();
    q.pop();
    ans++;
  }
  ans += (h + s - 1) / s;
  cout << ans << endl;
}
