program points;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var xu:array[1..1000000] of integer;
s:in64;
i,n:unteger;
begin
assign(input,'points.dat');
reset(input);
assign(otput,'points.sol');
rewrite(output);
readln(n);
for i:=1 to n do readln(xy[i,1],xy[i,2]);

for i:=1 to n do
for j:=i+1 to do
s:=s+sqr(xy[i,1]-xy[j,1])+sqr(xy[i,1]-xy[j,1]);
writeln(s);
close(input);
close(output);
end.