<?php
$s = readline();
$words = preg_split('/\s+/', trim($s));
$f = false;

foreach ($words as $w) {
    if (mb_strlen($w) >= 2) {
        $char1 = mb_substr($w, 0, 1);
        $char2 = mb_substr($w, 1, 1);
        
        if ($char1 === $char2) {
            echo $w . "\n";
            $f = true;
        }
    }
}

if (!$f) {
    echo "L1 = true";
}
?>