#include<iostream>
#include<sort>
using namespace std;
int main()
{
  int N;
  long long H;
  int x;  
  cin>>N>>H;
  long long a[100000],b[100000];
  for(int i=1;i<=N;i++)
  {
     cin>>a[i]>>b[i];
     a[i]=max(a[i],a[i-1]);
     x=a[i];} 
  sort(b,b+N); 
  int ans=0;
  for(int j=1;j<=N;j++)
  {
     if(x<=b[j] and H>0)
     { H=H-b[j];
       ans++;}
  }
  if(H>0)
  //cout<<ans;
  //cout<<(H+x-1)/x;
  cout<<(H+x-1)/x+ans<<endl;
  else 
  cout<<ans<<endl;
  system ("pause");
  return 0;
}