#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 1;
const long long M = 1e18;
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  long long n, h, s = 0, md = 0, x, y;
  cin >> n >> h;
  priority_queue<long long> q;
  for (int i = 0; i < (n); i++) {
    cin >> x >> y;
    q.push(y);
    md = max(md, x);
  }
  while (h > 0 && q.size()) h -= q.top(), s++, q.pop();
  while (h > 0) h -= md, s++;
  cout << s << endl;
}
