#include<iostream>
#include<algorithm>
#include<string>
using namespace std;

int main() {
  int N,H;
  cin>>N>>H;
  int a[100001],b[100001];
  for(int i=0;i<100001;i++){
    cin>>a[i]>>b[i];
  }
  sort(a,a+N);
  reverse(a,a+N);
  sort(b,b+N);
  reverse(b,b+N);
  int cont;
  cont=0;
  for(int i=0;i<N;i++){
    if(b[i]>=a[0] && H>0){
      cont+=1;
      H-=b[i];
    }
  }
  if(H>0){
    cont+=(H-1)/a[0]+1;}
  cout<<cont<<endl;
}
