Please explain how 0 is the output?

Question

a = [23,11,18,75,99]
p= ages.count(99)-ages.count(11)
print(p)

Answer 1

count() function returns the number of instances of the passed argument in the given list.
Ex : ages. count (99), returns number of 99 in the list named ages...

Answer 2

a.count(99) == 1
There is 1 int with the value 99
a.count(11) == 1
There is 1 int with value 11
p = 1 - 1
p = 0