Make achivement

Hi, I'm new to MCreator and lately i thought of a custom achievement mod. Let me explain, so you will get the achievement Reaper from killing a total of 100,000 undead (any) mobs.

So first i have the element (achievement) itself in workspace: https://imgur.com/a/84ftce2
Let's talk about the problem now. So i created a procedure here https://imgur.com/a/FCbrLQH since i can't code much in the uh element thing (https://imgur.com/a/Yz6DzEi).
The problem here is i can't seem to find a block to check if player has killed 100,000 any undead mobs yet so it can grant the achivement.
 

Hope you can help, thank you!