using System; 

public class Exam{ 

    static string[] E    = new string[] {"band", "bond", "bear", "cars", "fond", "food", "foot", "hand", "head"};

    static string sResult;

    static bool IsMatchOn3Characters(string s1, string s2)

    {

        for (int i = 0; i < s1.Length - 1; i++)

        {

           if (s2.IndexOf(s1.Substring(i,2)) >= 0)

              return true; // match

        }

        return false; // no match

    }

    public static void Main(String []args) 

    {     

        string M1, M2; 

        string sResult="";

        Console.Write( 

        "Enter the first string : "); 

        M1 = Console.ReadLine(); 

​

        Console.Write( 

        "Enter the second string : "); 

        M2 = Console.ReadLine(); 

        Console.Write( 

        "\nString transformation are : "); 

        sResult=M1;

        foreach (string s in E)

        {

            if (IsMatchOn3Characters(M1,s)) 

            {

                M1=s;

                sResult = sResult + ", " + s;

                if (M1==M2)

                    break;

            }

        }

        Console.Write(sResult);

    } 

}