N:=21; X:=y^4 + (3*x^2 + 1)*y^3 + (x^5 + x^4 + 2*x^2 + 2*x)*y^2 + (2*x^4 + x^3 + x)*y + x^3; r:=1+(y^2+y)*(x*y+y+1)/((x*y+1)*(x*y-y^2+1)); s:=1+(y^2+y)/(x*y+1); E:=[s-r*s+1,r*s-r^2*s,r*s-r^2*s,0,0]; P:=[0,0];