Digital Clock with an alarm

Hello everyone..I'm designing a digital clock using 7490 ic, 7447 ic and seven segment displays..I've completed the seconds and minutes portion...This clock is to be built in a 12 hr format....I couldn't figure out how to display 1 after 12 because it resets to zero...I have to display 1 after 12 and not 0. So, how do I do this? Hope you got the question...Also, I'm thinking of adding an alarm facility too..Any ideas regarding this?

You could count 0 to 11 then add 1.
You could add a circuit that looks for "0" and then forces a extra count.

See here. Solve many times on this site.

https://www.electro-tech-online.com/threads/ttl-clock-with-7447-7490-and-7400-ics.25628/