NO

1 decompositions
 #0 -----------
   1: +(0(),y) -> y
   2: +(s(x),y) -> s(+(x,y))
   3: +(x,+(y,z)) -> +(+(z,y),x)
   4: s(s(x)) -> x

unjoinable peak
    +(_y12,_y13)
*<- +(0(),+(_y12,_y13)) ->*
    +(+(_y13,_y12),0())