I want it to search string like `"$12,56,450"` using Regex in c#, but it doesn't match the string

Here is my code:

```
string input="Total earn for the year $12,56,450";
string pattern = @"\b(?mi)($12,56,450)\b";

Regex regex = new Regex(pattern);

  if (regex.Match(input).Success)
  {
     return true;
  }

```