package 郵便配達;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;

public class Main {
	InputStream is;
	PrintWriter out;
	String INPUT = "";

	void solve() {
		double[] a = new double[8];
		for (int i = 0; i < 8; i++)
			a[i] = nd();
		double[] b = new double[8];
		for (int i = 0; i < 8; i++)
			b[i] = nd();
		double ret = 0;
		int Z = 100;
		double Q = 0;
		for (int x = -Z; x <= Z; x++) {
			for (int y = -Z; y <= Z; y++) {
				for (int z = -Z; z <= Z; z++) {
					for (int i = 0; i < 8; i++) {
						double xx = x, yy = y, zz = z;
						if (i << ~0 < 0)
							zz += 0.5;
						if (i << ~1 < 0)
							yy += 0.5;
						if (i << ~2 < 0)
							xx += 0.5;
						if (xx == 0 && yy == 0 && zz == 0)
							continue;
						if (Math.sqrt((xx + 0.5) * (xx + 0.5) + (yy + 0.5) * (yy + 0.5) + (zz + 0.5) * (zz + 0.5)) > Z)
							continue;
						ret += a[i] / Math.sqrt(xx * xx + yy * yy + zz * zz);
						Q -= a[i];
					}
					for (int i = 0; i < 8; i++) {
						double xx = x + 0.25, yy = y + 0.25, zz = z + 0.25;
						if (i << ~0 < 0)
							zz += 0.5;
						if (i << ~1 < 0)
							yy += 0.5;
						if (i << ~2 < 0)
							xx += 0.5;
						if (xx == 0 && yy == 0 && zz == 0)
							continue;
						if (Math.sqrt((xx + 0.5) * (xx + 0.5) + (yy + 0.5) * (yy + 0.5) + (zz + 0.5) * (zz + 0.5)) > Z)
							continue;
						ret += b[i] / Math.sqrt(xx * xx + yy * yy + zz * zz);
						Q -= b[i];
					}
				}
			}
		}
		ret += Q / Z;
		out.printf("%.6f\n", ret);
	}

	void run() throws Exception {
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);

		long s = System.currentTimeMillis();
		solve();
		out.flush();
		if (!INPUT.isEmpty())
			tr(System.currentTimeMillis() - s + "ms");
		// Thread t = new Thread(null, null, "~",
		// Runtime.getRuntime().maxMemory()){
		// @Override
		// public void run() {
		// long s = System.currentTimeMillis();
		// solve();
		// out.flush();
		// if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
		// }
		// };
		// t.start();
		// t.join();
	}

	public static void main(String[] args) throws Exception {
		new Main().run();
	}

	private byte[] inbuf = new byte[1024];
	private int lenbuf = 0, ptrbuf = 0;

	private int readByte() {
		if (lenbuf == -1)
			throw new InputMismatchException();
		if (ptrbuf >= lenbuf) {
			ptrbuf = 0;
			try {
				lenbuf = is.read(inbuf);
			} catch (IOException e) {
				throw new InputMismatchException();
			}
			if (lenbuf <= 0)
				return -1;
		}
		return inbuf[ptrbuf++];
	}

	private boolean isSpaceChar(int c) {
		return !(c >= 33 && c <= 126);
	}

	private int skip() {
		int b;
		while ((b = readByte()) != -1 && isSpaceChar(b))
			;
		return b;
	}

	private double nd() {
		return Double.parseDouble(ns());
	}

	private char nc() {
		return (char) skip();
	}

	private String ns() {
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while (!(isSpaceChar(b))) { // when nextLine, (isSpaceChar(b) && b != '
									// ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}

	private char[] ns(int n) {
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while (p < n && !(isSpaceChar(b))) {
			buf[p++] = (char) b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}

	private int[] na(int n) {
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = ni();
		return a;
	}

	private long[] nal(int n) {
		long[] a = new long[n];
		for (int i = 0; i < n; i++)
			a[i] = nl();
		return a;
	}

	private char[][] nm(int n, int m) {
		char[][] map = new char[n][];
		for (int i = 0; i < n; i++)
			map[i] = ns(m);
		return map;
	}

	private int[][] nmi(int n, int m) {
		int[][] map = new int[n][];
		for (int i = 0; i < n; i++)
			map[i] = na(m);
		return map;
	}

	private int ni() {
		return (int) nl();
	}

	private long nl() {
		long num = 0;
		int b;
		boolean minus = false;
		while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
			;
		if (b == '-') {
			minus = true;
			b = readByte();
		}

		while (true) {
			if (b >= '0' && b <= '9') {
				num = num * 10 + (b - '0');
			} else {
				return minus ? -num : num;
			}
			b = readByte();
		}
	}

	private static void tr(Object... o) {
		System.out.println(Arrays.deepToString(o));
	}
}