public static void Main()
int middlePageNumber = (int)(Math.Ceiling((decimal)groupSize / 2));
int pagesBeforeMiddle = groupSize - (int)middlePageNumber;
int pagesAfterMiddle = groupSize - (pagesBeforeMiddle + 1);
if (pageNumber >= middlePageNumber && pageNumber - pagesBeforeMiddle > 0) {
startPage = pageNumber - pagesBeforeMiddle;
pagesAfterMiddle = groupSize - pageNumber;
if (pageCount >= (pageNumber + pagesAfterMiddle)) {
endPage = (pageNumber + pagesAfterMiddle);
bool showFirstButton = startPage > 1;
bool showLastButton = endPage < pageCount;
Console.WriteLine(middlePageNumber);
Console.WriteLine(startPage);
Console.WriteLine(endPage);