Phone numbers

### 题面描述 给一串长度为 $n$ 的数字串，在两个或三个数字之间加`-`，使得这个数字串便于记忆。如果有多解，可随意输出其中一个。 ### 数据范围与约定 $2\leq n\leq 100$

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.

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.

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.

6
549871

54-98-71

7
1198733

11-987-33