function calculate(unitPrice, PostingPrice)
{

	var count = document.getElementById("pocet");
	var OrderCount = count.value;
	var PriceHolder = document.getElementById("cena");
	var PriceHolder2 = document.getElementById("display_cena");
	var Price = (OrderCount * unitPrice) - (Math.floor(OrderCount / 11) * unitPrice) + Number(PostingPrice);
	PriceHolder.setAttribute("value", Price);
	PriceHolder2.setAttribute("value", Price);
}