process.stdin.resume();
process.stdin.setEncoding('utf8');
 
let input = '';
 
process.stdin.on('data', function(chunk) {
    input += chunk;
});
 
process.stdin.on('end', function() {
    const words = input.trim().split(/\s+/);
    for (const word of words) {
        const result = reader(word.trim());
        console.log(result);
    }
});
 
function reader(str) {
    const uniqueChars = [...new Set(str)].join('');
    return str === uniqueChars ? str : '';
}

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cXdlcmYgYWFkbmpuIGxvcG4gamtqbG9w

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