Input TRS:
    1: f(el(x),y) -> f(x,el(y))
    2: f(x,y) ->= f(l(x),y)
    3: f(x,y) ->= f(x,r(y))
    4: l(el(x)) ->= el(l(x))
    5: el(r(x)) ->= r(el(x))
Number of strict rules: 1
Direct Order(PosReal,>,Poly) ... removes: 1
     r(x1)	weight: x1
     l(x1)	weight: x1
     f(x1,x2)	weight: x2 + 2 * x1
    el(x1)	weight: (/ 1 4) + x1
Number of strict rules: 0
YES