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