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

const int size_d = 100000;


int main(){
  int n, h, maxa = 0, work, ans=0;
  int b[100000];

  
  cin >> n >> h;

  for(int i=0; i<n; ++i){
    cin >> work >> b[i];
    maxa = max(maxa, work);
  }


  sort(b, b+n);
  //  reverse(b, b+n);

  int cnt=n-1;
  while(h > 0){

    if(cnt>=0 && b[cnt] > maxa){
      h -= b[cnt];
      --cnt;
    }else{
      h-=maxa;
    }
    ++ans;
  }

  cout << ans << endl;
  
  return 0;
}
