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 Go (1.6) (judge verdict: Accepted)

package main
import (
    "fmt"
)
    
func main(){
    var N, ans int
    fmt.Scan(&N)
    for i, div, mod:=3, N/3, N/3;div>1;i+=2{
        div, mod = N/i, N%i
        if mod == 0 {
            continue
        }
        i+=mod/div-1
        if mod%div == 0{
            ans += i
        }
        
    }
    fmt.Println(ans)
}