Problem Statement

Snuke received a positive integer N from Takahashi.
A positive integer m is called a favorite number when the following condition is satisfied:

• The quotient and remainder of N divided by m are equal, that is$, \lfloor \frac{N}{m} \rfloor = N \bmod m$ holds.

Find all favorite numbers and print the sum of those.

Input

Input is given from Standard Input in the following format:
N

Output

Print the answer.

Constraints

• All values in input are integers.
• $1 \leq N \leq 10^{12}$

Sample Input 1

8

Sample Output 1

10

There are two favorite numbers: 3 and 7. Print the sum of these, 10.

Sample Input 2

1000000000000

Sample Output 2

2499686339916

Watch out for overflow.

见题面 Input 部分

见题面 Output 部分