YES

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

@Jouannaud and Kirchner's criterion
--- R
   1: +(x,y) -> +(y,x)
   2: +(x,0()) -> x
   3: +(x,s(y)) -> s(+(x,y))
   4: +(+(x,y),z) -> +(x,+(y,z))

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