if ($input =~ /^(y|yes)$/) {
        say "Backup is beginning...";
        last;
    }
    elsif ($input =~ /^(n|no)$/) {
        die "Program is shutting down.\n";
    }
    else {
        say "This is not a valid answer.";
        say "Please enter 'yes' or 'no'";
    }