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: Accepted)

using System;
using System.Collections.Generic;//list用
using System.Text;//StringBuilder用
using System.Collections;
using System.Linq;
class Program
{
    static List<int> s = new List<int>();
      static List<string> a = new List<string>();
    static decimal result;
static StringBuilder sb = new StringBuilder();
static decimal N,M,K;
    static void Main()
    {
Read1();
    //(m+1)x=N
//m>0
      //Nの約数で見ていく
      for(int x=1;(double)x<Math.Sqrt((double)N);x++){
      if(N%x==0 && x*(x+1)<N){
       result+=N/x-1;    
      }
      }
                   Console.WriteLine(result.ToString());

    }


    static void Read1()//1項
    {
        string tmp = Console.ReadLine();
        N = decimal.Parse(tmp);
    }
 
    static void Read2()//複数項（項目数Ｎ）
    {
        string[] tmp = Console.ReadLine().Split(' ');
        for (int i = 0; i < N; i++) { s.Add(int.Parse(tmp[i])); }
    }
    static void Read3()//1行複数項
   {
       string[] tmp = Console.ReadLine().Split(' ');
       for (int i = 0; i < tmp.Length; i++) { s.Add(int.Parse(tmp[i])); }
    }
    static void Read4()//NK１行
    {
        string[] tmp = Console.ReadLine().Split(' ');
       N = int.Parse(tmp[0]);
       K = int.Parse(tmp[1]);
    }
    static void Read5()//N行K項
    {
for(int i=0;i<N;i++){
a.Add(Console.ReadLine());
}
 
    }


}