15/1
(3/2 & 3/4 & 1/4)
(3/2 | 1/2 | 1/4)
((1/2 | 2/3) & 2/5)
(1/2 & (2/3 | 2/5) & 3/2)
(((1/2 | 2/3) & 2/5) | (1/2 & (2/3 | 2/5) & 3/2))