How do I make health sistem like The Biding Of Isaac?

I want do something like that

bindingofisaacrebirth.gamepedia.com/Hearts_(Pickup)

red harth and soul heart

You can create 3 instance variables: redHearts, maxRedHearts, soulHearts

On red heart pick up, set redHearts to min(redHearts+1, maxRedHearts)

On soul heart pick up, add 1 to soulHearts.

.

When character is hit:

If soulHearts>0, subtract 1 from soulHearts.

If soulHearts=0, check if redHearts>0, subtract 1 from redHearts.

If both redHearts and soulHearts are zero, character dies.

Thanks