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 <algorithm>
#include <cmath>
#include <vector>
#include <string>
#include <queue>
#include <utility>
#include <map>
#include <bitset>
#include <numeric>
#define ll long long
using namespace std;
using p = pair<ll, ll>;
ll dx[8]={ 0, 1, 0,-1, 1, 1,-1,-1}; // x軸方向への変位
ll dy[8]={ 1, 0,-1, 0, 1,-1, 1,-1}; // y軸方向への変位

ll n;
string a;
vector<string> ans;
string c = "abcdefghijklm";

int main(void) {
    ll n;
    cin >> n;
    ll ans = 0;
    for(ll i = 1; i < sqrt(n); i++){
        ll check = n-i;
        if(check%i==0) ans+=check/i;
        //cout << i << " " << check << endl;
    }
    cout << ans << endl;
    return 0;
}