of x2 we can just sum those together divide by that sum and that will normalize it make this sum to 1 and get the actual conditional now the model we have is this hmm like models so how do we write out this thing over here it's equal to the sum over variables we have ignored because we have a chain in how the probability distribution is set up and we left out x0 and x1 but as you write out the Joint Distribution they'll appear in it so we'll sum out over x0 and x1 and then we can write out the full chain rule for this hmm