ive got a project to do using macro programming but i cant seem to figure out looping.

the problem is to enter a 4 character number (i.e. 8075) and to get the macro to return a number. so with the number 8075 the returned number should be 3 because there is 3 circles. 2 in the number 8 and 1 in the number 0. so for 5071 it would return a 1 because there is only one circle in the number.

i can get it return a number if i only enter 1 number using the if-then stantment.
plz help and show codes if entered if possible! in need of help.