#include <bits/stdc++.h>
using namespace std;

int main() {
  int N,H;
  cin >> N >> H;
  vector<int> a(N),b(N);
  for (int i=0;i<N;i++){
    cin >> a[i] >> b[i];
  }
  sort(a.begin(),a.end());
  sort(b.begin(),b.end());
  int x=a[N-1];
  int ans=0;
  for (auto itr=--b.end();itr>=lower_bound(b.begin(),b.end(),x);itr--){
    int y=*itr;
    H-=y;
    ans++;
    if (H<=0){
      break;
    }
  }
  if (H>0){
    ans+=(H+x-1)/x;
  }
  cout << ans << endl;
}