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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>
#include<string>
#include<bits/stdc++.h>
using namespace std;

int main()
{
   unsigned long long int n,k,i,j,sum=0,count=0;
   cin>>n;const unsigned int M = 1000000007; 
   sum=((n-1)%M)+(((n/2)-1))%M+(((n/4)-1))%M;
   for(i=1;i<(n/4)-1;i++)
   {  
       if((n/i)==(n%i))
       {  //cout<<i<<" ";
           sum=(sum+i)%M;
       }
           
   }
   
      cout<<(sum)%M<<endl;
   
   return 0;
}