n = int(input())

n_s = int(n**(1/2))


def eratosthenes(limit: int, minLimit: int = None):
    if minLimit and (minLimit < 0 or minLimit > limit):
        raise ValueError("incorrect minLimit")
    isPrime = [True] * max(limit + 1, 2)
    isPrime[0] = False
    isPrime[1] = False
    for p in range(2, limit + 1):
        if not isPrime[p]:
            continue
        for i in range(p * p, limit + 1, p):
            isPrime[i] = False
    if minLimit:
        return [i for i, x in enumerate(isPrime[minLimit:], start=minLimit) if x]
    else:
        return [i for i, x in enumerate(isPrime) if x]

primes = eratosthenes(n_s)

s = 0
i = 63
for p in primes:
    while p**i > n:
        i -= 1
    s += (p**(i+1)-1)/(p-1)-(1+p)

print(int(s))