y = 1;
                r = (a * a) % m;
                for (int i = 0; i <= stepen.Length-1; i++)
                {
                    if (i >= stepen.Length-1)
                    {
                        if (ch[i] == '1')
                            y = (y * a) % m;
                    }
                    else
                    {
                        if (ch[i] == '1')
                            y = ((y * y) * r) % m;
                        else { y = (y * y) % m; }
                    }

 r = a;
                if (x % 2 == 0)//четное
                    y = 1;
                else//нечетное
                    y = a;
                label16.Text = label16.Text + y.ToString() + ". ";
                for (int i = stepen.Length - 2; i >= 0; i--)
                {
                    r = (r * r) % m;
                        if (ch[i] == '1')
                            y = (y * r) % m;
                }