program TinhTong;
uses crt;
var
n, i, tong: integer;
begin
clrscr;
write('Nhap vao so nguyen duong n: ');
readln(n);
tong := 0;
for i := 1 to n-1 do begin
if i mod 2 <> 0 then
tong := tong + i;
end;
writeln('Tong cac so khong chia het cho 2 la: ', tong);
readln;
end.