def divisors(n):
    divs = []
    for d in range(1, int(n**0.5) + 1):
        if n % d == 0:
            divs.append(d)
            q = n // d
            if q != d:
                divs.append(q)
    return divs

def divisors2(n):
    divs = []
    lim = int(n**0.5)
    d = 1
    while d <= lim:
        if n % d == 0:
            divs.append(d)
            q = n // d
            if q != d:
                divs.append(q)
        d += 1
    return divs

print(sum(divisors2(int(input()))))