问题1246--Phone numbers

1246: Phone numbers

时间限制: 1 Sec  内存限制: 128 MB
提交: 302  解决: 130
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题目描述

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 three digits. For example, the phone number 119733 is easier to remember as 119-733. Your task is to find for a given phone number divisions into groups of three digits.

输入

N cases,Each case the first line contains integer n (3 ≤ n ≤ 100) (n is a multiple of 3
)— amount of digits in the phone number. The second line contains n digits — the phone number to divide into groups.

输出

Output divisions of the given phone number into groups of three digits. Separate groups by single character -.

样例输入 Copy
2
6
549871
3
117
样例输出 Copy
549-871
117

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