#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
#define all(x) (x).begin(),(x).end()
#define ll long long
int main(){
  ll N,H;
  cin>>N>>H;
  vector<ll> A(N),B(N);
  rep(i,N) cin>>A[i]>>B[i];
  sort(all(A));
  sort(all(B));
  int ans=0;
  for(int i=N-1;i>=0;i--){
    if(B[i]>=A[N-1]&&H>0){
      H-=B[i];
      ans++;
    }else break;
  }
  if(H>0) ans+=(H+A[N-1]-1)/A[N-1];
  cout<<ans<<endl;
}