def gen_passwd_list(passwd_len, charset = "012", limit = 0):
    ret = []
    if (type(charset) != 'list'):
        charset_ = charset
        charset = []
        for x in charset_:
            charset.append(x)

    passwd = []
    for i in range(passwd_len):
        passwd.append(0)

    # comb_count = pow(len(charset), len(passwd))

    def _passwd(passwd):
        ret = ""
        for x in passwd:
            ret+=charset[x]
        return ret

    charset_len = len(charset)
    last = passwd_len-1
    while 1:
        ret.append(_passwd(passwd))
        if (limit):
            if (len(ret) == limit):
                break
        passwd[last] += 1
        if (passwd[last] == charset_len):
            passwd[last] = 0

            pos = last-1
            while pos >= 0:
                passwd[pos] += 1
                if (passwd[pos] == charset_len):
                    passwd[pos] = 0
                    pos -= 1
                    continue
                break

            if pos < 0:
                break
    return ret


charset = "0123456789"

pp = gen_passwd_list(4,charset)
for p in pp:
    print p