Sucet cifier

//Sucet cifier x
program sucetcifierx;
{$APPTYPE CONSOLE}
uses SysUtils;
type cifra=1..9;
var cf:cifra;
    c:longint;
    s:byte;
begin
  write('Zadajte cislo: ');
  readln(c);
  while c<>0 do
    begin
      cf:= c mod 10;
      c:= c div 10;
      s:=s+cf;
    end;
  writeln(s);
  readln;
end.