#include <bits/stdc++.h>
using namespace std;
#define rep(i,m,n) for(int i=m;i<n;i++)
using ll=long long;

int main() {
  int n;
  ll h;
  cin>>n>>h;
  ll a[n];
  ll b[n];
  rep(i,0,n){
    cin>>a[i]>>b[i];
  }
  ll c=0;
  rep(i,0,n){
    c=max(c,a[i]);
  }
  sort(b,b+n);
  ll ans=0;
  rep(i,0,n){
    if(b[n-1-i]<c) break;
    h-=b[n-1-i];
    ans++;
    if(h<=0) break;
  }
  if(h>0) ans+=(h+c-1)/c;
  cout<<ans<<endl;
}
