log（2)[log（3)(log(4) x)] = 0
log（3)(log(4) x) = 1
log(4) x = 3
x = 64
log(3)[log(4) (log(2) y)] = 0
log(4)(log(2) y) = 1
log(2) y = 4
y = 16
所以 x + y = 80