def solve():
    n = int(input())
    
    sosu = [2,3]
    for i in range(5, 10**5+1, 2):
        for j in sosu:
            if i % j == 0:
                break
        else:
            sosu.append(i)
    ans = 0
    for i in sosu:
        if i > n:
            break
        tmp = i
        while tmp * i <= n:
            tmp *= i
            ans += tmp
    print(ans)

if __name__ == "__main__":
    solve()