(VAR x y)
(RULES
   +(0,0) -> 0
   +(s(x),y) -> s(+(x,y))
   +(x,s(y)) -> s(+(y,x))
)
(COMMENT
doi:10.4230/LIPIcs.FSCD.2016.33
[36] Example 1
submitted by: Takahito Aoto
)