#include<bits/stdc++.h>
using namespace std;
long N,H,i,a,max_a,t,cnt;
vector<long>b;
int main(){
  cin>>N>>H;
  b.resize(N);
  for(i=0;i<N;i++){
    cin>>a>>b[i];
    max_a=max(max_a, a);
  }
  sort(b.begin(),b.end());
  while(H>0&&!b.empty()){
    t=b.back();
    if(t<=max_a)break;
    cnt++;
    H-=t;
    b.pop_back();
  }
  if(H>0)cnt+=(H+max_a-1)/max_a;
  cout<<cnt<<endl;
  return 0;
}
