How do I tell the program to catch an error where the user enters something that is not recognised? E.G. instead of USD or EURO, they enter 40 or sdfsdf or 4f43f. Thanks

```
Console.WriteLine("This is a Currency Converter --- Ver A1.00");

Console.WriteLine("----------------------------");

Console.WriteLine("----------------------------");

Console.WriteLine("Enter the amount of money:");

value = Convert.ToDouble(Console.ReadLine());

Console.WriteLine("");

Console.WriteLine("Great, Now we must select which currency you want to convert to:");

Console.WriteLine("Type: USD or EURO");

Console.WriteLine("----------------------------");

Rate = Console.ReadLine();

try

{

}

catch

{
     Console.WriteLine("Enter a number:");
}

```