An integer x is called a proper divisor of an integer y if x is a divisor of y and 1 <= x < y.
Let us denote as s(a) the sum of all proper divisors of a. An integer a is called almost perfect by k if |a-s(a)| <= k.
You are given ints left, right and k. Return the number of integers between left and right, inclusive, that are almost perfect by k.
|-||left will be between 2 and 1000, inclusive.|
|-||right will be between left and 1000, inclusive.|
|-||k will be between 0 and 1000, inclusive.|