<?php
 
if (php_sapi_name() !== 'cli') {
    fwrite(STDERR, "Run this script from the terminal.\n");
    exit(1);
}
 
$list = [];
while (($line = fgets(STDIN)) !== false) {
    $item = rtrim($line, "\r\n");
    if ($item === '') {
        continue;
    }
    $list[] = $item;
}
 
$result = [];
 
foreach ($list as $item) {
    $res = IsItsCharsAppearsTwice($item);
    if ($res) {
        $result[] = $res;
    }
}
 
foreach ($result as $word) {
    echo $word, PHP_EOL;
}
 
function IsItsCharsAppearsTwice($word)
{
    $map = [];
    $len = strlen($word);
 
    for ($i = 0; $i < $len; $i++) {
        $char = $word[$i];
        $map[$char] = ($map[$char] ?? 0) + 1;
    }
 
    foreach ($map as $char => $count) {
        if ($count == 2) {
            return $word;
        }
    }
    return null;
}
 
 

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YXNkZgpmZGFzCmFzZHMKZCBmbQpkZmFhCmFhYWEKYWFiYgphYWFiYg==

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