program valik;
uses crt;
var
 tekst:array[1..10]of string;
 erinev, kokku, i: integer;
 abi: string;



procedure alusta;
begin
 clrscr;
 tekst[1]:='Esimene rida';
 tekst[2]:='Teine rida  ';
 tekst[3]:='Kolmas rida ';
 tekst[4]:='Neljas rida ';
 kokku:=4;
 erinev:=1;
 textbackground(white);
 textcolor(black);
 gotoxy(10, 5);
 write(tekst[1]);
 textbackground(black);
 textcolor(white);
 for i:=2 to kokku do begin
  gotoxy(10, 4+i);
  write(tekst[i]);
 end;
end;

procedure muuda(uus: integer);
begin
 textcolor(white);
 textbackground(black);
 gotoxy(10, 4+erinev);
 write(tekst[erinev]);
 erinev:=uus;
 textcolor(black);
 textbackground(white);
 gotoxy(10, 4+erinev);
 write(tekst[erinev]);
end;


begin
 alusta;
 repeat
  abi:=readkey;
  if abi=chr(0) then begin
   abi:=readkey;
   if abi='H' then begin
      if erinev>1 then muuda(erinev-1) else
         muuda(kokku);
   end;
  if abi='P' then begin
      if erinev<kokku then muuda(erinev+1) else
         muuda(1);
   end;
  end;


 until (abi=chr(27)) or (abi=chr(13));
  if abi=chr(13) then begin
     textcolor(white);
     textbackground(black);
     gotoxy(50, 20);
     write('Valisid rea number ',erinev,'.');
     readln;
  end;
TextMode(LastMode);
end.