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


chomp( my $user_char = <STDIN> );
my $regex = '[a-z' . quotemeta($user_char)  .']+';
$regex = qr{ ^ $regex $ }x;

print $regex, $/;


while ( my $line = <DATA> ) {
    if ( $line =~ $regex ) {
        print "ja: $line\n";
    }
    else {
        print "ne: $line\n";
    }
}
#

__DATA__
string.print
string_print