N = int(input())

limit = 10**5
distinct_prime_factor_count = [0]*(limit+1)
primes = []
for i in range(2, limit+1):
    if distinct_prime_factor_count[i] == 0:
        primes.append(i)
        for num in range(i, limit+1, i):
            distinct_prime_factor_count[num] += 1

# 全探索する
ans = 0
for n in range(2, 34):
    for p in primes:
        if p**n > N:
            break
        else:
            ans += p**n

print(ans)