var n:longint;
function f(t:Longint):longint;
begin
if t=1 then f:=1
else f:=f(t-1)+t*t;
end;
begin
readln(n);
writeln(f(n));
end.
var n:longint;
function f(t:Longint):longint;
begin
if t=1 then f:=1
else f:=f(t-1)+t*t;
end;
begin
readln(n);
writeln(f(n));
end.