Problems
Longge`s problem
Longge`s problem
Longge is good at mathematics, and he likes to think about hard mathematical problems which will be solved by some graceful algorithms. Now a problem comes:
Given an integer $n$. Compute $∑gcd(i, n)$ for all $1 \le i \le n$.
"Oh, I know, I know!" Longge shouts! But do you know? Please solve it.
\InputFile
Each line contains one number $n~(1 < n < 2^{31})$.
\OutputFile
For each number $n$ print in a separate line the sum $∑gcd(i, n)$ for all $1 \le i \le n$.
Input example #1
2 6 12
Output example #1
3 15 40