Check if we can make a triangle

program trikampis_bendrai;
  uses crt;
  var a, b, c : integer;
      r : char;
  label start;
begin
start:ClrScr;
 a := 0;
 b := 0;
 c := 0;
repeat                   //kartojam kol yra nuliniu reiksmiu
     ClrScr;
    TextColor (white);
   GotoXY (2,2);
  Write ('Ivesk trikampio krastines, atskirtas tarpais: ');
    Read (a, b, c);
     if (a > 0) and (b > 0) and (c > 0) then      //tikrinam ar yra nuliniu reiksmiu
      begin
       GotoXY (2,3);
        Write ('Neteisingos reiksmes!');
       Delay (2000);
       end;
{      Repeat
     ClrScr;
   GotoXY (2,2);
  Write ('Ivesk trikampio krastines, atskirtas tarpais: ');
    Read (a, b, c); }
     until (a >= 1) or (b >= 1) or (c >= 1);    //kai nebera nuliniu reiksmiu pradedam likusia daly
      //end
     //else
      //begin
       if (a + b > c ) and (a + c > b) and (b + c > a) then   //jaigu dvieju atkarpu suma didesne uz treciaja tai
          begin
           GotoXY (3,4);
             TextColor (green);
            Write ('Trikampty sudaryti galima!');
          end
       else
          begin
           GotoXY (3,4);
             TextColor (red);
            Write ('Trikampy sudaryti negalima!');
          end;
  GotoXY (2,5);
   Write ('Kartoti?: ');
    Read (r);
     r := readkey;
     Case r of
        't' : Goto Start;
        'n' : halt;
     end;
   //end;
end.