I have the following in my c# code - what I like it to do is to check to see if the expression has numbers or a dash but nothing else. If I type in the letter K along with a dash or number it still accepts it. How do I say just have the express be numbers or a dash:

```
     Match match = Regex.Match(input, @"[0-9-]");

```

Note that input is the text that I am passing for evalution.