#!/usr/bin/perl
use strict; use warnings;

my @ranges = ('15', '28-31', '3-4', '40', '17-19');
my ($total_min, $total_max);

foreach my $range (@ranges) {
  my ($min) = $range =~ /^(\d+)/;
  my ($max) = $range =~ /(\d+)$/;
  $total_min += $min;
  $total_max += $max;
}

print "total is between $total_min and $total_max\n";