Sum of Unique Prime Factors

Given an integer \(n\) satisfying \(2 \le n \le 10^{12}\), compute the sum of its unique prime factors. The unique prime factors of \(n\) are the distinct prime numbers that exactly divide \(n\). Each prime factor is counted only once in the sum.

For example, for \(n = 28\), the prime factors are 2 and 7, and their sum is \(2 + 7 = 9\).

inputFormat

The input consists of a single line containing one integer \(n\) where \(2 \le n \le 10^{12}\).

outputFormat

Output a single integer which is the sum of the unique prime factors of \(n\).

28

9