N:=18;
X:=y^2 + (x^3 - 2*x^2 + 3*x + 1)*y + 2*x;
r:=(x^2 - x*y - 3*x + 1)/((x-1)^2*(x*y+1));
s:=(x^2 - 2*x - y)/(x^2 - x*y - 3*x - y^2 - 2*y);
E:=[s-r*s+1,r*s-r^2*s,r*s-r^2*s,0,0];
P:=[0,0];