const
  oo=maxlongint div 2;

var
  n,ans,j,i,nn:longint;
  h,age,q,d,last:array[0..1000000]of longint;
  w,c:array[0..2002,0..2002]of longint;
  v:array[0..100000]of boolean;

function spfa:boolean;
var
  h,x,i,t:longint;
begin
  h:=1;
  t:=1;
  q[1]:=0;
  for i:=0 to n do
  begin
    v[i]:=false;
    d[i]:=oo;
    last[i]:=-1;
  end;
  d[0]:=0;
  v[0]:=true;
  repeat
    x:=q[h];
    for i:=0 to n do
    if (c[x,i]>0)and(d[x]+w[x,i]<d[i]) then
    begin
      d[i]:=d[x]+w[x,i];
      last[i]:=x;
      if not v[i] then
      begin
        v[i]:=true;
        inc(t);
        q[t]:=i;
      end;
    end;
    v[x]:=false;
    inc(h);
  until h>t;
  if d[n]=oo then exit(false);
  exit(true);
end;

procedure change;
var
  i:longint;
begin
  i:=n;
  while last[i]<>-1 do
  begin
    dec(c[last[i],i]);
    inc(c[i,last[i]]);
    i:=last[i];
  end;
end;

begin
  assign(input,'christmas.in'); reset(input);
  assign(output,'christmas.out'); rewrite(output);
  readln(n);
  for i:=1 to n+n do
  begin
    readln(h[i],age[i]);
  end;
  for i:=1 to n do
   for j:=n+1 to n+n do
   begin
     c[i,j]:=1;
     w[i,j]:=sqr(h[i]-h[j])+sqr(age[i]-age[j]);
     w[j,i]:=-w[j,i];
   end;
  for i:=1 to n do
	  c[0,i]:=1;
  for i:=n+1 to n+n do
	  c[i,n+n+1]:=1;
  nn:=n;
  n:=n+n+1;
  while spfa do change;
  ans:=-oo;
  for i:=1 to nn do
   for j:=nn+1 to nn+nn do
   if (c[i,j]=0)and(w[i,j]>ans) then ans:=w[i,j];
  writeln(ans);
  close(input);
  close(output);
end.