var N,S: integer;
begin
readln(N);
if N<=1 then
begin
while n<=1 do
begin
s:=n+s;
n:=n+1;
end;
end
else
begin
while n>=1 do
begin
s:=s+n;
n:=n-1;
end;
end;
writeln(S);
end.
 Pascal
Zaranie po>I<@luicta

You can solve it with more faster algorithm.
Just use the sum of arithmetic progression =)