#!/usr/bin/perl -w
use strict;
use Calendar::Functions qw(month_days dotw dotw3);

while (1) {
    print "Enter year (yyyy) and month (mm), separated by a space:";
    chomp(my $input = <STDIN>);
    last if !$input;

    my ($year, $month) = split / /, $input;
    my $dayname = dotw(dotw3(month_days($month, $year), $month, $year));

    print "The last day of $month/$year will be a $dayname\n";
}