YES

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

@Mutually Orthogonal
--- R
   1: +(0(),y) -> y
   2: +(s(0()),y) -> s(y)
   3: +(s(s(x)),y) -> s(s(+(y,x)))

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