mod = 998244353
NN = 5*10**7
eps = 10**-9


def main():
    import sys
    from math import sqrt, floor
    input = sys.stdin.readline

    P_list = [1] * (NN+1)
    for p in range(2, NN+1):
        if P_list[p] == 1:
            for d in range(1, NN+1):
                if p*d > NN:
                    break
                P_list[p*d] *= p

    N = int(input())
    ans = 0
    for a in range(1, N+1):
        if P_list[a] == a:
            ans += floor(sqrt(N // a)) ** 2
    print(ans)


if __name__ == '__main__':
    main()