import sys

sys.setrecursionlimit(2*10**5)


def input(): return sys.stdin.readline().rstrip('\n')


def isp(x):
    i = 2
    while i*i <= x:
        if x % i == 0:
            return False
        i += 1
    return True


def main():
    N = int(input())

    ans = 0
    n = 2
    while 2**n <= N:
        p = 2
        while p**n <= N:
            if isp(p):
                ans += p**n
            p += 1

        n += 1

    print(ans)


if __name__ == '__main__':
    main()