(VAR x y c)
(RULES
times(x,y) -> help(x,y,0)
help(x,y,c) -> if(lt(c,y),x,y,c)
if(true,x,y,c) -> plus(x,help(x,y,s(c)))
if(false,x,y,c) -> 0
lt(0,s(x)) -> true
lt(s(x),0) -> false
lt(s(x),s(y)) -> lt(x,y)
plus(x,0) -> x
plus(0,x) -> x
plus(x,s(y)) -> s(plus(x,y))
plus(s(x),y) -> s(plus(x,y))
)