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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
public class Main {
    public static void main(String[] args){
        Main start=new Main();
        start.start();

    }
    public Main(){
    }
    public void start(){
        Scanner sc = new Scanner(System.in);
        // 整数の入力
        long N = sc.nextLong();
        long result=0;
        for(int i=1;i<Math.sqrt(N);i++){
            if(N%i==0&&i*(i+1)<N){
             result=result+(N/i-1);
            }
        }
        System.out.println(result);

    }
    int gcd (int a, int b) {
        int temp;
        while((temp = a%b)!=0) {
            a = b;
            b = temp;
        }
        return b;
    }
}