Need a text box help in PerlTk

I need a text box setting in perlTk such that i can enter 2 digit number with automatically added separator.

Eg. if there are 5 entries of two digits number namely 52, 25, 69, 45, 15, in text box if i enter these five 2 digits numbers the separator (-) should automatically added after every two digit entry.

and final entry would look like 52 - 25 - 69 - 45 - 15 Please not that separator should automatically inserted.

This is somewhat similar to below gif. enter image description here