Найти одинаковые слова в разных текстах - C#

int counterZ = 0;
            int counterM = 0;
 
            string Z1 = "";
 
            string[] massiveOfStringZ1 = System.IO.File.ReadAllLines("emotsiiZ.txt");
            foreach (string s in massiveOfStringZ1)
            {
                Z1 += s;
            }
 
            string[] Z11 = Z1.Split(' ');
 
            string[] words = richTextBox1.Text.Split(new char[] { ' ' });
 
            for (int i = 0; i < words.Count(); i++)
            {
                for (int j = 0; j < Z11.Count(); j++)
                    if (words.Contains(Z11[j]))
                    {
                        counterZ++;
                    }
                if (words.Count() == 0 || Z11.Count() == 0)
                    break;
            }