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# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;

namespace AtcoderProgram
{
    class Program
    {
        static void Main(string[] args)
        {

            Int64 res = 0;
            Int64 num = Int64.Parse(Console.ReadLine());

            for (Int64 i = 1; i < num; i++)
            {
                if (i * i >= num) break;
                if ((num) % i == 0)
                {
                    res += ((num - i) / i);
                }
            }

            Console.WriteLine(res);
        }
    }
}