#include<bits/stdc++.h>
using namespace std;
using ll=long long;
using P=pair<ll,ll>;

int main(){
  ll n,k;
  cin>>n>>k;
  vector<ll> x(n+2),y(n+2);
  for(ll i=0;i<=n+1;i++){
    cin>>x[i]>>y[i];
  }
  ll ok=1e18,ng=0;
  while(abs(ok-ng)>1){
    ll mid=(ok+ng)/2;
    vector<ll> dist(n+2,1e18);
    dist[0]=0;
    priority_queue<P,vector<P>,greater<P>> que;
    que.push(P(dist[0],0));
    while(que.size()){
      P q=que.top();
      que.pop();
      ll d=q.first;
      ll from=q.second;
      if(dist[from]<d){
        continue;
      }
      for(ll to=0;to<=n+1;to++){
        ll next=d+max((ll)0,(abs(x[to]-x[from])+abs(y[to]-y[from])-1)/mid);
        if(dist[to]>next){
          dist[to]=next;
          que.push(P(dist[to],to));
        }
      }
    }
    if(dist[1]<=k){
      ok=mid;
    }else{
      ng=mid;
    }
  }
  cout<<ok<<endl;
}