How do I check Distance but in reverse and with a limit?

I want to get the distance from the blue and red sprite but only when you enter the circle and the closer you get, the higher the number, with 0 being the on the circle line and 100 being on the red sprite.

value=max(0,(circleradius-distance(blue.x,blue.y,red.x,red.y))/circlradius*100)

value=max(0,(circleradius-distance(blue.x,blue.y,red.x,red.y))/circlradius*100)

works perfect, thanks