import sys,heapq
input = sys.stdin.buffer.readline
n=int(input())
def make_divisors(n):
  divisors=[]
  for i in range(1,int(n**0.5)+1):
    if n%i==0:
      divisors.append(i)
      if i!=n//i:
        divisors.append(n//i)

  divisors.sort()
  return divisors
D=make_divisors(n)
ans=0
for d in D:
  if d%2==1 or (n//d)%2==0:
    ans+=d
print(ans)