A 3$$\times$$3 matrix is filled with the numbers from 31 to 39 according to the following rules :
(a) 38 is above 39 and to the right of 32
(b) 33 is to the right of 37 and above 39 which is to the left of 34
(c) 32 is to the left of 35
(d) 37 is above 36 and 32
(e) 31 is above 35
'Above' and 'below' mean that they are in the same column while 'left' and 'right' mean that the numbers are in the same row.
What is the sum of the numbers in the middle row?