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: Wrong Answer)

import java.util.Scanner;
public class Main{
	public static void main(String[] args){
		// TODO 自動生成されたメソッド・スタブ
		Scanner scan=new Scanner(System.in);
		//恐らくO(logN)orO(1)だと思う
		long a=scan.nextLong();
		long ans=0;
		for(long i=1;i<a;i++) {//iはあまりの数
			long minus=a-i;
			if(minus%i==0) {
				ans+=minus/i;
			}
			if(i*i>a) {
				break;
			}
		}
		System.out.println(ans);
	}
}