import math;
n = int(input());
s = 0
for i in range(2,int(math.sqrt(n)) + 1):
  if n % i == 0:
     if i * i == n:
       s = s + i;
     else:   
       s = s + i + n // i;
  
print(s)

/**************************************************************
	Problem: 1084
	User: admin
	Language: Python
	Result: Accepted
	Time:134 ms
	Memory:34480 kb
****************************************************************/