import sys

def enumerate_print(L, k):
    if k == len(L):
        print(L)
        return
    for i in range(len(L)):
        L[k] = i
        enumerate_print(L, k + 1)

def enumerate(N):
    L = N * [0]
    enumerate_print(L, 0)

def main():
    N = int(sys.argv[1])
    enumerate(N)

main()

# $ python enumerate.py 3
# [0, 0, 0]
# [0, 0, 1]
# [0, 0, 2]
# [0, 1, 0]
# [0, 1, 1]
# [0, 1, 2]
# [0, 2, 0]
# [0, 2, 1]
# [0, 2, 2]
# [1, 0, 0]
# [1, 0, 1]
# ...
# $