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

#define fi first
#define se second
#define repl(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define rep(i,n) repl(i,0,n)
#define each(itr,v) for(auto itr:v)
#define pb(s) push_back(s)
#define mp(a,b) make_pair(a,b)
#define all(x) (x).begin(),(x).end()
#define dbg(x) cout<<#x"="<<x<<endl
#define maxch(x,y) x=max(x,y)
#define minch(x,y) x=min(x,y)
#define uni(x) x.erase(unique(all(x)),x.end())
#define exist(x,y) (find(all(x),y)!=x.end())
#define bcnt(x) bitset<32>(x).count()

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef pair<P, int> PPI;
typedef pair<ll, ll> PL;
typedef pair<P, ll> PPL;

#define INF INT_MAX/3

#define MAX_N 1000

int n;
int x[3003],y[3003];
char aru[5555][5555];

int main(){
	cin.sync_with_stdio(false);
  while(1){
    memset(aru,0,sizeof(aru));
    cin>>n;
    if(n==0)break;
    rep(i,n){
      cin>>x[i]>>y[i];
      aru[x[i]][y[i]]=true;
    }
    int res=0;
    rep(i,n)rep(j,i){
      int x3=x[i]+y[i]-y[j];
      int y3=y[i]+x[j]-x[i];
      int x4=x[j]+y[i]-y[j];
      int y4=y[j]+x[j]-x[i];
      int dx=x[i]-x[j],dy=y[i]-y[j];
      if(x3>=0&&y3>=0&&x4>=0&&y4>=0&&x3<=5000&&y3<=5000&&x4<=5000&&y4<=5000&&aru[x3][y3]&&aru[x4][y4]){
        maxch(res,dx*dx+dy*dy);
      }
    }
    cout<<res<<endl;
  }
  return 0;
}