using System;

public class Program

{

    public static void Main()

    {

        bool result = Equals("tatia","ti");

        Console.WriteLine(result);

    }

        static bool Equals(string str1, string str2)

        {

            int counter = 0;

            if (str1.Length < str2.Length)

            {

                return false;

            }

            for (int i = 0; i < str1.Length; i++)

            {

                char char1 = str1[i];

                char char2 = str2[counter];

                if (char1 == char2)

                {

                    counter++;

                }

                else 

                {

                    counter = 0;

                }

                if (counter == str2.Length)

                {

                    return true;

                }

            }

            return false;

        }

}

​

​