(VAR w x x1 x2 x3 x4 y z )
(RULES 
        f1(a, x) -> g1(x, x)
        f1(x, a) -> g2(x, x)
        f2(a, x) -> g1(x, x)
        f2(x, a) -> g2(x, x)
        g1(a, x) -> h1(x)
        g1(x, a) -> h2(x)
        g2(a, x) -> h1(x)
        g2(x, a) -> h2(x)
        h1(a) -> i
        h2(a) -> i
        e1(h1(w), h2(w), x, y, z, w) -> e2(x, x, y, z, z, w)
        e1(x1, x1, x, y, z, a) -> e5(x1, x, y, z)
        e2(f1(w, w), x, y, z, f2(w, w), w) -> e3(x, y, x, y, y, z, y, z, x, y, z, w)
        e2(x, x, y, z, z, a) -> e6(x, y, z)
        e2(i, x, y, z, i, a) -> e6(x, y, z)
        e3(x1, x1, x2, x2, x3, x3, x4, x4, x, y, z, w) -> e4(x1, x1, x2, x2, x3, x3, x4, x4, x, y, z, w)
        e3(x, y, x, y, y, z, y, z, x, y, z, a) -> e6(x, y, z)
        e4(g1(w, w), x1, g2(w, w), x1, g1(w, w), x1, g2(w, w), x1, x, y, z, w) -> e1(x1, x1, x, y, z, w)
        e4(i, x1, i, x1, i, x1, i, x1, x, y, z, a) -> e5(x1, x, y, z)
        e4(x, x, x, x, x, x, x, x, x, x, x, a) -> e6(x, x, x)
        e5(i, x, y, z) -> e6(x, y, z)
        
)