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 (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
#include <math.h>

int main(void)
{
	long long int n,m;
	
	long long int sum = 0;
	
	
	
	scanf("%lld",&n);
	
	
	for(m = 1;m* m <= n;m++){
		if(n % m == 0){
			long long int temp = n/m - 1;			//割り切れた数でnを割ると約数が出てくる。
			if(n / m - 1 == n % m - 1){
				sum = sum + m;
			}
			if(temp != 0){
				if(n / temp == n % temp){
				sum = sum + temp;
				}
			}
		}
	}
		
	printf("%lld\n",sum);
	
	return 0;
	
}