#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int N, H, x, y, ans = 0;
  vector<long long int> a, b;
  cin >> N >> H;
  while (N--) {
    cin >> x >> y;
    a.push_back(x);
    b.push_back(y);
  }
  sort(a.begin(), a.end());
  sort(b.begin(), b.end());
  int i = b.size() - 1;
  int j = a.size() - 1;
  while (b[i] >= a[j] && i >= 0) {
    if (H <= 0) break;
    H -= b[i];
    ans++;
    i--;
  }
  ans += ((H + a[j] - 1) / a[j]);
  cout << ans << endl;
  return 0;
}
