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)

#include <stdio.h>
#include <math.h>
#include <stdlib.h>

int main(){
    long long int N;
    scanf("%lld", &N);

    long long int i, j, ans=0, cnt=0;
    long long int P[100000];
    for (i=1; ;i++){
        if (N%i == 0) {
            P[cnt] = i;
            cnt++;
            P[cnt] = N/i;
            cnt++;
        }
        if (i >= N/i) break;
    }

    for (i=0; i<cnt; i++){
        if (N/P[i] < P[i]) ans += (P[i]-1);
    }
    


    printf("%lld", ans);
    return 0;
}