YES

1 decompositions
 #1 -----------
   1: s(p(x1)) -> x1
   2: p(s(x2)) -> x2
   3: +(x3,0()) -> x3
   4: +(x4,s(x5)) -> s(+(x4,x5))
   5: +(x6,p(x7)) -> p(+(x6,x7))
   6: +(0(),x8) -> x8
   7: +(p(x9),x10) -> p(+(x9,x10))
   8: +(s(x11),x12) -> s(+(x11,x12))

@Knuth and Bendix' criterion
--- R
   1: s(p(x1)) -> x1
   2: p(s(x2)) -> x2
   3: +(x3,0()) -> x3
   4: +(x4,s(x5)) -> s(+(x4,x5))
   5: +(x6,p(x7)) -> p(+(x6,x7))
   6: +(0(),x8) -> x8
   7: +(p(x9),x10) -> p(+(x9,x10))
   8: +(s(x11),x12) -> s(+(x11,x12))

--- S
   1: s(p(x1)) -> x1
   2: p(s(x2)) -> x2
   3: +(x3,0()) -> x3
   4: +(x4,s(x5)) -> s(+(x4,x5))
   5: +(x6,p(x7)) -> p(+(x6,x7))
   6: +(0(),x8) -> x8
   7: +(p(x9),x10) -> p(+(x9,x10))
   8: +(s(x11),x12) -> s(+(x11,x12))