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 Python (3.8.2) (judge verdict: Accepted)

N = int(input())
ans = 0
for i in range(1,min(N,1250000)):
    if(((N-i)/i).is_integer() and N//((N-i)/i) == N%((N-i)/i)):
        # print((N-i)//i,i)
        ans += ((N-i)//i)
        # if(i == 800000):
        #     print(ans)
    # print(i)
print(ans)