#include #include #include using namespace std; int main(){ double a,b,c,d,e,f;cin>>a>>b>>c>>d>>e>>f; double A = a; double B = b; double aa = -c/(2*A); double bb = -d/(2*B); double r2 = aa*aa+bb*bb-(e-f); cout << fixed << setprecision(10) << sqrt(r2) << endl; }