timer(24,_,_):-!.
timer(H,60,S):-Hnew is H+1,timer(Hnew,1,S),!.
timer(H,M,60):-Mnew is M+1,timer(H,Mnew,1),!.
timer(H,M,S):-H>12,Hprint is H-12,printZero(Hprint),write(Hprint),write(':'),printZero(M),write(M),write(':'),printZero(S),write(S),write(' PM'),nl,Snew is S+1,timer(H,M,Snew).
timer(H,M,S):-H=<12,printZero(H),write(H),write(':'),printZero(M),write(M),write(':'),printZero(S),write(S),write(' AM'),nl,Snew is S+1,timer(H,M,Snew).

startDay:-timer(0,1,1).

%-- Print 0 before one digit (extra point)
printZero(X):-X<10,write('0'),!.
printZero(_).