using static System.Console;

int ms = -1;

int[] Data = { 5, 1, 29, 185, 10, 8, 17, 36, 3, 81, 48, 49 };

foreach (int x in Data) {

    if ((x % 2 == 0) && (x > ms))

        ms = x;

}

WriteLine(ms);

​