CF25B.Phone numbers

Phone number in Berland is a sequence of n digits. Often, to make it easier to memorize the number, it is divided into groups of two or three digits. For example, the phone number 1198733 is easier to remember as 11-987-33. Your task is to find for a given phone number any of its divisions into groups of two or three digits.

俄罗斯贝兰德的电话号码是由 n 个数字组成的序列。为了便于记忆，人们常将其划分为若干组，每组包含两个或三个数字。例如，电话号码 1198733 可被更易记地表示为 11-987-33。你的任务是：对给定的一个电话号码，找出其任意一种划分为若干组（每组含两个或三个数字）的方式。

The first line contains integer n (2 ≤ n ≤ 100) — amount of digits in the phone number. The second line contains n digits — the phone number to divide into groups.

第一行包含一个整数 $n$（$2 \leq n \leq 100$）—— 电话号码的位数。
第二行包含 $n$ 个数字 —— 待分组的电话号码。

Output any of divisions of the given phone number into groups of two or three digits. Separate groups by single character -. If the answer is not unique, output any.

将给定的电话号码划分为若干组，每组包含两个或三个数字。各组之间用单个字符 - 分隔。如果答案不唯一，则输出任意一个即可。