program program4; const ...

program program4;
const
    u: array[0..2] of integer = (1, -3, 2);
    v: array[0..1] of integer = (-2, 3);
var
    i, n, sum: integer;
function g(n: integer): integer;
var i, sum: integer;
begin
    sum := 0;
    for i := 1 to n do inc(sum, u[i mod 3] * i);
    g := sum;
end;
begin
    sum := 0;
    read(n);
    for i := 1 to n do inc(sum, v[i mod 2] * g(i));
    writeln(sum);
end.