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


def main():
    import sys
    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

    root = [0] * (NN+1)
    for i in range(1, NN+1):
        if i*i > NN:
            break
        for j in range(i*i, (i+1)**2):
            if j > NN:
                break
            root[j] = i

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


if __name__ == '__main__':
    main()