NO

1 decompositions
 #1 -----------
   1: +(0(),x1) -> x1
   2: +(s(x2),x3) -> s(+(x2,x3))
   3: +(x4,+(x5,x6)) -> +(+(x6,x5),x4)
   4: s(s(x7)) -> x7

unjoinable peak
    +(x19,x20)
*<- +(0(),+(x19,x20)) ->*
    +(+(x20,x19),0())