public static long taumBday(long noOfBlackGifts, long noOfWhiteGifts, long blackGiftPrice, long whiteGiftPrice, int conversionCost) {
    if(conversionCost < Math.abs(blackGiftPrice-whiteGiftPrice)) {
        if(blackGiftPrice < whiteGiftPrice) {
            whiteGiftPrice = blackGiftPrice + conversionCost;
        } else if(whiteGiftPrice < blackGiftPrice){
            blackGiftPrice = whiteGiftPrice + conversionCost;
        }
    }
    return (noOfBlackGifts * blackGiftPrice) + (noOfWhiteGifts * whiteGiftPrice);
}