import math

N = int(input())

def primes(x : int) -> list[int]:
    if x < 2:
        return []
    nums = [i for i in range(x)]
    nums[1] = 0

    for num in nums:
        if num == 0:
            continue
        for nonp in range(2 * num, x, num):
            nums[nonp] = 0
    return [p for p in nums if p != 0]

P = primes(int(math.sqrt(N)) + 1)
s = 0
for p in P:
    l = int(math.log(N, p)) + 1
    if l <= 2:
        continue
    s += int((p ** l - p ** 2) / (p - 1))

print(s)