checking file exist or not in the sharepoint document library using c#

  I am trying to check whether file is available in the document library or not .... but i am getting error like item doesn't exist for this code,could you please help me in this   

  bool Filexists = false;
            using (var clientContext = new ClientContext("https://"))
            {

                var list = clientContext.Web.Lists.GetByTitle("Details");
                var listItem = list.GetItemById(0);
                clientContext.Load(list);
                clientContext.Load(listItem, i => i.File);
                clientContext.ExecuteQuery();
                Filexists = listItem!=null ? true : false;
            }
            return Filexists;