### 1246: Phone numbers

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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.

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.

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

2
6
549871
3
117


549-871
117