(VAR X X1 X2 X3 Y )
(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)
        
)