(1/(2r-2)-1/(r-1+l))EllipticPi(((3r+2l)(r-1))/(r+l-1)^2,arccos(1-(2l)/(sqrt2.+r+l)),(2+3r/l)/4)/sqrt l-2.805949177929332444089 ,where r=(cbrt(108+12sqrt69)+cbrt(108-12sqrt69))/6,l=sqrt(3r^2-1)