import java.awt.*; import java.io.*; import java.util.ArrayList; import java.util.StringTokenizer; import java.util.stream.IntStream; public class D_CanYouDrawACircle { private static final BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); private static final PrintWriter pw = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out))); private static StringTokenizer st; private static int readInt() throws IOException { while (st == null || !st.hasMoreTokens()) st = new StringTokenizer(br.readLine()); return Integer.parseInt(st.nextToken()); } public static void main(String[] args) throws IOException { solve(); pw.close(); } private static void solve() throws IOException { double a = readInt(); double b = readInt(); double c = readInt(); double d = readInt(); double e = readInt(); double f = readInt(); assert a == b; // a x 2 + b y 2 + c x + d y + e = f // r * r = (f-e-4 * c * c/a - 4 * d * d/b)/a double r = Math.sqrt((f - e + c * c / a / 4 + d * d / b / 4) / a); // wrong?! pw.printf("%.5f\n", r); } }