main = do
let f = count '(' l
s = count ')' l
Y291bnQgYyBsID0gbGVuZ3RoICQgZmlsdGVyIChjPT0pIGwKIAptYWluID0gZG8gCiAgICAgICAgbCA8LSBnZXRMaW5lCiAgICAgICAgbGV0IGYgPSBjb3VudCAnKCcgbAogICAgICAgICAgICBzID0gY291bnQgJyknIGwKICAgICAgICBwdXRTdHJMbiAkIHNob3cgZiArKyAiICIgKysgc2hvdyBzICsrICIgIiArKyBzaG93IChmPT1zKQ==
KHgwICsgeDIwbiAtICgociAtIHIyKSoociArIHIyKSooeDAgLSB4MjBuKSkvKFBvd2VyKHgwIC0geDIwbiwyKSArIFBvd2VyKHkwICZuZGFzaDsgeTIwbiwyKSkpLzIu
(x0 + x20n - ((r - r2)*(r + r2)*(x0 - x20n))/(Power(x0 - x20n,2) + Power(y0 – y20n,2)))/2.