program points2;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var x,y:array[0..1000000] of integer;
var i,n             : longint;
   ans, sum, sum2 : int64;
begin
assign(input,'points.dat');
reset(input);
assign(output,'points.sol');
rewrite(output);
readln(n);
for i:=1 to n do readln(x[i],x[i]);

   ans := 0;
   sum := 0;
   sum2 := 0;
   for i:= 0 to n-1 do begin
      ans := ans + int64(i) * x[i] * x[i] - 2 * x[i] * sum + sum2;
      sum := sum + x[i];
      sum2 := sum2 + x[i] * x[i];
   end;

 { solve }
{   sum := 0;
   sum2 := 0;
   for i:= 0 to n-1 do begin
      ans := ans + int64(i) * y[i] * y[i] - 2 * y[i] * sum + sum2;
      sum := sum + y[i];
      sum2 := sum2 + y[i] * y[i];
   end;}



     writeln(ans);


close(input);
close(output);
end.