def walk(left, right, ret_buf):
    if right < left:
        return
    elif right == 0:
        print ret_buf
        return

    if left > 0:
        walk(left - 1, right, ret_buf + "(")
    if right > 0:
        walk(left, right - 1, ret_buf + ")")

if __name__ == "__main__":
    n = 3
    walk(n, n, "")