NO

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

unjoinable peak
    +(_y261,x)
*<- +(s(x),s(_y261)) ->*
    +(x,_y261)