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Problem2251--[POJ2480]Longge's problem

2251: [POJ2480]Longge's problem

Time Limit: 1 Sec  Memory Limit: 128 MB  Submit: 0  Solved: 0
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Description

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(1 < N < 231),you are to calculate ∑gcd(i, N) 1<=i <=N.
"Oh, I know, I know!" Longge shouts! But do you know? Please solve it.

Input

Input contain several test case.
A number N per line.

Output

For each N, output ,∑gcd(i, N) 1<=i <=N, a line

Sample Input Copy

2
6

Sample Output Copy

3
15

Source/Category