(VAR Y X X1 X2 X3)
(RULES 
active(minus(0,Y)) -> mark(0)
active(minus(s(X),s(Y))) -> mark(minus(X,Y))
active(geq(X,0)) -> mark(true)
active(geq(0,s(Y))) -> mark(false)
active(geq(s(X),s(Y))) -> mark(geq(X,Y))
active(div(0,s(Y))) -> mark(0)
active(div(s(X),s(Y))) -> mark(if(geq(X,Y),s(div(minus(X,Y),s(Y))),0))
active(if(true,X,Y)) -> mark(X)
active(if(false,X,Y)) -> mark(Y)
mark(minus(X1,X2)) -> active(minus(X1,X2))
mark(0) -> active(0)
mark(s(X)) -> active(s(mark(X)))
mark(geq(X1,X2)) -> active(geq(X1,X2))
mark(true) -> active(true)
mark(false) -> active(false)
mark(div(X1,X2)) -> active(div(mark(X1),X2))
mark(if(X1,X2,X3)) -> active(if(mark(X1),X2,X3))
minus(mark(X1),X2) -> minus(X1,X2)
minus(X1,mark(X2)) -> minus(X1,X2)
minus(active(X1),X2) -> minus(X1,X2)
minus(X1,active(X2)) -> minus(X1,X2)
s(mark(X)) -> s(X)
s(active(X)) -> s(X)
geq(mark(X1),X2) -> geq(X1,X2)
geq(X1,mark(X2)) -> geq(X1,X2)
geq(active(X1),X2) -> geq(X1,X2)
geq(X1,active(X2)) -> geq(X1,X2)
div(mark(X1),X2) -> div(X1,X2)
div(X1,mark(X2)) -> div(X1,X2)
div(active(X1),X2) -> div(X1,X2)
div(X1,active(X2)) -> div(X1,X2)
if(mark(X1),X2,X3) -> if(X1,X2,X3)
if(X1,mark(X2),X3) -> if(X1,X2,X3)
if(X1,X2,mark(X3)) -> if(X1,X2,X3)
if(active(X1),X2,X3) -> if(X1,X2,X3)
if(X1,active(X2),X3) -> if(X1,X2,X3)
if(X1,X2,active(X3)) -> if(X1,X2,X3)
)