#include <bits/stdc++.h>
using namespace std;

int main(){
  int64_t N,H;
  cin>>N>>H;
  vector<int64_t> a(N),b(N);
  for(int i=0;i<N;++i) cin>>a[i]>>b[i];

  sort(a.begin(),a.end());
  sort(b.begin(),b.end());

  int iter=b.end()-lower_bound(b.begin(),b.end(),a[N-1]);

  int64_t cnt=0;
  
  for(int i=N-1;i>N-1-iter;--i){
    H -= b[i];
    ++cnt;
    if(H<=0) break;
  }
  
  if(H>0){
    cnt += (H+a[N-1]-1)/a[N-1];
  }

  cout<<cnt<<endl;
}