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: Runtime Error)

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		try (Scanner in = new Scanner(System.in)) {
			long n = in.nextLong();

			long r = 0;
			long d = 0;
			
			long end = (long)Math.sqrt(n) + 1;
			while (d <= end) {
				d++;
				
				long x = (n - d);
				if (x % d == 0) {
					long f = x / d;
					if (d % f == 0) {
						continue;
					}
					//System.out.println(f);
					r += f;
				}
				
			}
			
			System.out.println(r);
		}
	}
	
}