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 <bits/stdc++.h>
using namespace std;
#define MIN(a, b) ((a) <= (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
int gcc(int n){
	int r=0;
	for(int i=1;i<=n;i++){
		if(n%i==0){
			++r;
		}
	}
	return r;
}
int main(){
	long n,ans;
	ans = 0;
	cin >> n;
	vector<long>r;
	for(long i=1;i<=n;i++){
		if(n%i==0){
			r.push_back(i);
		}
	}
	long num = r.size()/2;
	for(long i=0;i<num;i++){
		ans = ans + n/r[i]-1;
	}
	cout << ans << endl;
	
}