def gcd(a, b):
    if b==0:
        return a
    return gcd(b, a%b)
n=int(input())
g=gcd(n*(n+1)//2, n)
ans=0
for i in range(1, n+1):
    if i*i>n:
        break
    if n%i==0:
        ans+=i
        if i*i<n:
            ans+=n//i
print(ans)