static void Main() { string FileLoc; do { Console.Write("Enter File Location : "); FileLoc = Console.ReadLine().ToLower(); } while (!File.Exists(FileLoc) || !FileLoc.EndsWith(".pdf")); Start1: Console.Write("From Page : "); int.TryParse(Console.ReadLine(), out int from); if (from == default) { goto Start1; } Start2: Console.Write("To Page : "); int.TryParse(Console.ReadLine(), out int to); if (to == default) { goto Start2; } PDFParser p = new PDFParser(FileLoc, from, to); p.A_SaveExcel(); p.B_LoadExcels(); MainIterator iter = new MainIterator(p.Table); p.End(); }