i am getting this error in this code. "System.FormatException: 'Input string was not in a correct format.'" :         string[] rounds = cols[5].Split('|');

        foreach (string round in rounds)
        {
//splitting each round on "^"

          string[] msText = round.Split('^');
//create a new list in text file

          List<MatchupModel> ms = new List<MatchupModel>();
                    
         foreach (string matchupModelTextId in msText)
         {
this is the line on which i am getting "error.System.FormatException: 'Input string was not in a correct format.'

    ms.Add(matchups.Where(x => x.Id == int.Parse(matchupModelTextId)).First());
         
          }

          tm.Rounds.Add(ms);
                    
          }