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function validPESEL($str)
{
	if (!preg_match('/^[0-9]{11}$/',$str))
	{
		return false;
	}
 
	$arrSteps = array(1, 3, 7, 9, 1, 3, 7, 9, 1, 3); 
	$sum = 0;
	for ($i = 0; $i < 10; $i++)
	{
		$sum += $arrSteps[$i] * $str[$i]; 
	}
	$int = 10 - $sum % 10;
	$controlNr = ($int == 10)?0:$int;
	if ($controlNr == $str[10])
	{
		return true;
	}
	return false;
}