program dekripsi;

uses crt;

var
   F1, F2 : text;
   p: char;
   c : integer;
   k : integer;

begin
   assign(F1, 'cipher.txt');
   reset(F1);

   assign(F2, 'palin2.txt');
   rewrite(F2);

   write('k = ?'); readln(k);
   while not EOF(F1) do
    begin
      while not EOLN(F1) do
       begin
         read(F1, p);
         c := (ord(p) - k) mod 256;
         write(F2, chr(c));
       end;
       readln(F1);
       writeln(F2);
    end;

    close(F1);
    close(F2);

end.