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 (3.4.3) (judge verdict: Wrong Answer)

n=int(input())
r=int(n**(1/2))
ans=0
if r==1:
  if n==1 or n==2:
    print(0)
  else:
    print(1)
  
elif n==r*r:
  for i in range(1,r):
    if n%i==0:
      a=n//i
      if a-1>0:
        ans+=a-1
else:
  for i in range(1,r+1):
    if n%i==0:
      a=n//i
      if a-1>0:
        ans+=a-1
print(ans)