Two dice are thrown simultaneously. What is the probability of getting the sum of the face number is odd?

In a simultaneous throw of two dice, we have n(S) = 6 x 6 = 36
Let E = event of getting two numbers whose sum is odd.
Then E = {(1,2), (1,4), (1,6), (2,1), (2,3), (2,5), (3,2), (3,4), (3,6), (4,1), (4,3), (4,5), (5,2), (5,4), (5,6), (6,1), (6,3), (6,5)}
therefore, n(E) = 18
And P(E) = p( getting two numbers whose sum is odd)
P(E)= n(E)/n(S)
= 18/36
= 1/2