Variance of the Sum of Random Variables

Let X and Y be discrete random variables with the joint probabilities P(X=1, Y=2) = 0.1, P(X=1, Y=3) = 0.2, P(X=2, Y=1) = 0.3, and P(X=2, Y=2) = 0.4. What is the value of Var(X + Y)?