function getFacebookIdentifier($ProfileContent_result){

    if(preg_match('/"entity_id":([0-9]+)/', $ProfileContent_result, $matches)){
        return $matches[1];
    }

    return false;

}


function getFacebookProfileContent($name){

    return sendRequest('https://m.facebook.com/'.$name, [
        'User-Agent: Mozilla/5.0 (BB10; Kbd) AppleWebKit/537.10+ (KHTML, like Gecko) Version/10.1.0.4633 Mobile Safari/537.10+'
    ]);

}

function sendRequest($url, $headers = []){

    $ch = curl_init();

    curl_setopt_array($ch, [
        CURLOPT_URL => $url,
        CURLOPT_HTTPHEADER => $headers,
        CURLOPT_SSL_VERIFYHOST => 0,
        CURLOPT_SSL_VERIFYPEER => 0,
        CURLOPT_FAILONERROR => 1,
        CURLOPT_RETURNTRANSFER => 1
    ]);

    return curl_exec($ch);

}


$nome = 'inkeliz';

if($id = getFacebookIdentifier( getFacebookProfileContent($nome) )){

    echo $id;

}