I am trying to use regex in C# to edit string format.

Previous format is 09/08/2015 or 9/08/2015 and pattern I tried is `"([0-9]{1,}|[0-9]{2,})/[0-9]{2,}/[0-9]{4,}"`
New format should be 2015 08 09

I am trying to use variables from match, but it shows only $1 and not $2 or $3

```
string pattern = "([0-9]{1,}|[0-9]{2,})/[0-9]{2,}/[0-9]{3,}";
string replacement = "$3 $2 $1";
Regex rgx = new Regex(pattern);
string result = rgx.Replace(text, replacement);
richTextBox1.Text = result;

```

Please, help me to edit proper pattern format.

**EDIT:**  

I just forget to write, that at first I am loading data from .txt file and in that data I am replacing date format `31/03/2015` or `1/03/02` to `2015 03 31`.