import numba



@numba.njit

def main(N):

    x = 0

    for i in range(1,N+1):

        for j in range(i,N+1,i):

            x += j

    return x

N = int(eval(input()))

print((main(N)))
def main(N):

    x = 0

    for i in range(1,N+1):

        for j in range(i,N+1,i):

            x += j

    return x

N = int(eval(input()))

print((main(N)))
import numba


@numba.njit
def main(N):
    x = 0
    for i in range(1, N + 1):
        for j in range(i, N + 1, i):
            x += j
    return x


N = int(eval(input()))
print((main(N)))

def main(N):
    x = 0
    for i in range(1, N + 1):
        for j in range(i, N + 1, i):
            x += j
    return x


N = int(eval(input()))
print((main(N)))

-import numba - - -@numba.njit