Please explain how is the output 1

programming
Tags: #<Tag:0x00007f242ed3b630>

#1

A : "abbbc"B : “ab*c”

The expected returned value : 1


#2

a would be matched with a
ans b* means b can be occured 0 times or one times or two times …and so on…so b occure three times here.
and c would be matched with c