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 (Clang 3.8.0) (judge verdict: Wrong Answer)

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

long factorization(long N);

int main(void){
  long N;
  char str[100];
  
  fgets(str,sizeof(str),stdin);
  N=atol(str);
  
  
  printf("%ld\n",factorization(N));
  
  
  return 0;
}

long factorization(long N){
  long ans,i;
  
  for(i=1,ans=0;i*i<N;i++){
    if(N%i==0){
      ans+=N/i-1;
    }
  }
  
  return ans;
  
}