সি# \B রেজেক্স

using System;
using System.Text.RegularExpressions;
namespace MyApplication {
  class Program {
    static void Main(string[] args) {

    string text = "সি#পাইথন";
    string pattern = @"\Bপাইথন";

    foreach (Match match in Regex.Matches(text, pattern)) {
      Console.WriteLine(match.Value);
    }
    }
  }
}