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<cstdio>
#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<cmath>
#include<cstdlib>
#include<bitset>
#include<utility>
using namespace std;

unsigned long long n,num=0;


int main(void) {

	cin>>n;

	for (unsigned long long s = 1; s <= sqrt(n); s++) {
		if(n%s==0){
			num+=(n/s)-1;
			//cout<<s<<"\n";
			//cout<<(n/s)-1<<"\n";
		}
	}

	//cout<<num<<"\n";
	printf("%llu\n",num);

	return 0;
}