/*
https://beta.atcoder.jp/contests/abc085/tasks
*/
#include<iostream>
#include<algorithm> //sort
using namespace std;
typedef long long ll;

int main(){
  int n,H,m=0;
  cin>>n>>H;
  int a,b[n],ans=0;
  for(int i=0;i<n;i++){
    cin>>a>>b[i];
    if(m<a) m=a;
  }
  sort(b,b+n,[](const int& x, const int& y){return (x>y);} );

  for(int i=0;i<n&&H>0;i++){
    ans++; H-=max(m,b[i]);
  }
  if(H>0) ans+=(H+m-1)/m;
  cout<<ans<<"\n";
}
