NO

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

unjoinable peak
    +(x,_y12)
*<- +(p(s(x)),_y12) ->*
    p(+(_y12,s(x)))