how can i get AC

   var
   t1, t2, t3, t4 : real;
   a1, a2, a3, a4, x : integer;

begin
   readLn(t1, t2);
   read(t4, t3);
   if t1 > t2 then t2 := t2 + 24;
   if t4 > t3 then t3 := t3 + 24;
   a1 := TRUNC(t1);
   a2 := TRUNC(t2);
   a3 := TRUNC(t3);
   a4 := TRUNC(t4);
   t1 := (t1-a1)*5/3 + a1;
   t2 := (t2-a2)*5/3 + a2;
   t3 := (t3-a3)*5/3 + a3;
   t4 := (t4-a4)*5/3 + a4;
   x := TRUNC(abs(t1-t2+t3-t4)/2);
   writeLn(x);
end.