FormatException

using System;

class Program{

  public static void Main(){

    double num = 0;
    try{
      num = Convert.ToDouble("63.5@4");
    }
    catch (FormatException){
      Console.WriteLine("We encountered a FormatException");
    }
    catch (Exception){
      Console.WriteLine("Another Exception");
      throw;                                        // rethrowing
    }
    Console.WriteLine(num);
  }

}