Set active button after sprite animation.

I'm trying to make a simple logic game based only on UI elements. I want to set active two buttons after sprite animation, but i don't know how to do it. That is probably possible with using simple script, but i didn't found any by using google. I'm thinking about some frame counter (i know a number of frames of that animation), but also i don't know how count a frames by script. What is important, that solution should work also on other game objects, because later i will use it to set active a image. It's my first game and i'm fresh in Unity and C#, so be gentle.