var a, y, z, x: Real; begin Read(y, z, x); a := (4 * y + 2 * z * z) / (5 * x * Sqrt(z)); Write(a); end.
Begin
Read(y) ;
Read(z) ;
Read(x) ;
A:=(4*y+2*z*z)/(5*x*sqrt(z));
Write(a);
End.