Problem:
Score : 500 points

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.

Constraints

All values in input are integers.

1 \leq N \leq 10^{12}

Input

Input is given from Standard Input in the following format:

N

Output

Print the answer.

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.

Solution in C (GCC 5.4.1) (judge verdict: Wrong Answer)

//gcc 5.4.0

#include  <stdio.h>

int main(void)
{
    long N;
    long x;
    long res = 0;
    scanf("%ld", &N);
    for(x = 1; x < N; x++){
        if(N%x == 0){
            if(N/x == 2){
                continue;
            }
            res += N/x - 1;
        }
    }
    printf("%ld", res);
}