NO

1 decompositions
 #0 -----------
   1: b(b(b(x))) -> a(a(a(x)))
   2: a(a(a(x))) -> b(a(b(x)))

unjoinable peak
    b(b(a(b(x))))
*<- b(b(b(b(x)))) ->*
    b(a(b(b(x))))