> #include<iostream>
> using namespace std;
> #define N 50010
> #define MAX 100000
> struct Point {
> 	int x;
> 	int y;
> }P[N];
> int stack[N];
> int top;
> inline int  dirc(Point p1,Point p2,Point p3)  {
> 	return (p3.x-p1.x)*(p2.y-p1.y)-(p3.y-p1.y)*(p2.x-p1.x);
> }
> inline int range(Point p1,Point p2)  {
> 	return (p2.x-p1.x)*(p2.x-p1.x)+(p2.y-p1.y)*(p2.y-p1.y);
> }
> 
> int comp(const void* p1,const void* p2)  {
> 	int d=dirc(P[0],*(Point*)p1,*(Point*)p2);
> 	if(d==0) return range(P[0],*(Point*)p1)-range(P[0],*(Point*)p2);
> 	return d;
> }	
> int main()  {
> 	int n;
> 	while(scanf("%d",&n)!=EOF)  {
> 		top=-1;
> 		int i,j,pos=0,max=0,min=MAX;
> 	for(i=0;i<n;i++)   {
> 		scanf("%d%d",&P[i].x,&P[i].y);
> 		if(P[i].y<min)  {
> 			pos=i;
> 			min=P[i].y;
> 		}
> 	}
> 	swap(P[0],P[pos]);
> 	qsort(&P[1],n-1,sizeof(Point),comp);
> 	stack[++top]=0;
> 	stack[++top]=1;
> 	for(i=2;i<n;i++)  {
> 		int d=dirc(P[stack[top-1]],P[stack[top]],P[i]);
> 		if(d<0)	stack[++top]=i;
> 		else stack[top]=i;
> 	}
> 	for(i=0;i<top;i++)
> 		for(j=i+1;j<=top;j++)
> 			if(range(P[stack[i]],P[stack[j]])>max) {
> 				max=range(P[stack[i]],P[stack[j]]);
> 			}
> 	printf("%d\n",max);
> 	}
> 	return 0;
> }