@EventHandler
    public void onCraft(PrepareItemCraftEvent event) {
        if (event.getRecipe() != null){
            ItemStack result = event.getRecipe().getResult();


            if (result.hasItemMeta() && "Kevlar".equalsIgnoreCase(result.getItemMeta().getDisplayName())) {

                boolean foundspecial = false;
                for (ItemStack item: event.getInventory().getMatrix()) {

                    if (item != null && item.hasItemMeta()) {
                        if (item.getItemMeta().getDisplayName().equalsIgnoreCase("Plastic")) {
                            foundspecial = true;
                            break;
                        }
                    }
                }
                if (!foundspecial) {
                    event.getInventory().setResult(null);
                }
            }
            result.setAmount(checkMultiples(event));
            getLogger().info(result.getAmount());
        }
    }

    public Integer checkMultiples(PrepareItemCraftEvent event) {
        ArrayList<Integer> list = new ArrayList<Integer>();
        for (ItemStack item : event.getInventory().getMatrix()) {
            if (item != null) {
                list.add(item.getAmount());
            }

        }

        Integer temp = list.get(0);

        for (Integer amount : list) {
            if (amount < temp) {
                temp = amount;
            }
        }
        return temp;
    }

}