package q2xx;
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 Q281 {
	static InputStream is;
	static PrintWriter out;
	static String INPUT = "";
	
	static void solve()
	{
		int rem = 80-ni();
		double[] dead = new double[]{
				(double)ni()/100,
				(double)ni()/100,
				(double)ni()/100
		};
		int[] two = new int[1<<14];
		int[] zero = new int[1<<14];
		for(int i = 0;i < 1<<14;i++){
			two[i] = i&i>>>1&i<<1;
			zero[i] = i&~(i>>>1)&~(i<<1);
		}
		
		double[][] pows = new double[6][30];
		for(int j = 0;j < 3;j++){
			pows[j][0] = pows[j+3][0] = 1;
			for(int i = 1;i < 30;i++){
				pows[j][i] = pows[j][i-1] * dead[j];
				pows[j+3][i] = pows[j+3][i-1] * (1-dead[j]);
			}
		}
		
		double[] p = new double[1<<14];
		p[(1<<14)-1] = 1;
		for(int i = 0;i < rem;i++){
			double[] np = new double[1<<14];
			for(int j = 0;j < 1<<14;j++){
				int ntwo = Integer.bitCount(two[j]);
				int nzero = Integer.bitCount(zero[j]);
				int none = Integer.bitCount(j)-ntwo-nzero;
				for(int k = j;k >= 0;k--){ k &= j; 
					// j->k
					
					int netwo = Integer.bitCount((j^k)&two[j]);
					int nezero = Integer.bitCount((j^k)&zero[j]);
					int neone = Integer.bitCount(j^k)-netwo-nezero;
					double trans = 
							pows[2][netwo] * pows[5][ntwo-netwo] *
							pows[1][neone] * pows[4][none-neone] *
							pows[0][nezero] * pows[3][nzero-nezero];
//					double trans = 
//					Math.pow(dead[2], netwo) * Math.pow(1-dead[2], ntwo-netwo) *
//					Math.pow(dead[1], neone) * Math.pow(1-dead[1], none-neone) *
//					Math.pow(dead[0], nezero) * Math.pow(1-dead[0], nzero-nezero);
					np[k] += p[j] * trans;
				; } // include i=0
			}
			p = np;
		}
		double E = 0;
		for(int i = 0;i < 1<<14;i++){
			E += Integer.bitCount(i) * p[i];
		}
		out.printf("%.12f\n", E*2);
	}
	
	public static void main(String[] args) throws Exception
	{
		long S = System.currentTimeMillis();
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		solve();
		out.flush();
		long G = System.currentTimeMillis();
		tr(G-S+"ms");
	}
	
	private static boolean eof()
	{
		if(lenbuf == -1)return true;
		int lptr = ptrbuf;
		while(lptr < lenbuf)if(!isSpaceChar(inbuf[lptr++]))return false;
		
		try {
			is.mark(1000);
			while(true){
				int b = is.read();
				if(b == -1){
					is.reset();
					return true;
				}else if(!isSpaceChar(b)){
					is.reset();
					return false;
				}
			}
		} catch (IOException e) {
			return true;
		}
	}
	
	private static byte[] inbuf = new byte[1024];
	static int lenbuf = 0, ptrbuf = 0;
	
	private static 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 static boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private static int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private static double nd() { return Double.parseDouble(ns()); }
	private static char nc() { return (char)skip(); }
	
	private static 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 static 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 static 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 static int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private static int ni()
	{
		int num = 0, 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 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) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); }
}