#include <bits/stdc++.h>
using namespace std;
#define REP(i,n) for(int(i)=0;i<(n);i++)

int main(){
  int n,h,ans=0;cin>>n>>h;
  vector<int> a(n,0),b(n,0);
  REP(i,n) cin>>a.at(i)>>b.at(i);
  sort(a.begin(),a.end(),greater<int>());
  sort(b.begin(),b.end(),greater<int>());

  REP(i,n) if(a.at(0)<b.at(i)){
    h-=b.at(i);
    ans++;
    if(h<=0) break;
  }
  if(h>0) ans+=(h+a.at(0)-1)/a.at(0);

  cout<<ans;
}