using System;
using System.Text.RegularExpressions;

    class ExtractSentences
    {
        static void Main()
        {

            string text = "In this town. We are living in a yellow submarine. We don't have anything else. Inside the submarine is "
            + "very tight. So we are drinking all the day. We will move out of it in 5 days.";

            string word = "in";

            string[] sentences = text.Split('.');


            for (int i = 0; i < sentences.Length; i++)
            {
                if (Regex.IsMatch(sentences[i], @"\b" + word + @"\b", RegexOptions.IgnoreCase))
                {
                    Console.WriteLine((sentences[i] + ".").Trim());
                }
            }


        }
    }