import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.PriorityQueue;
import java.util.Queue;
public class Main {
	public static void main(String[] args) throws NumberFormatException, IOException{
		ContestScanner in = new ContestScanner();
		int a = in.nextInt();
		double p0 = in.nextInt();
		p0 *= 0.01;
		p0 = 1 - p0;
		double p1 = in.nextInt();
		p1 *= 0.01;
		p1 = 1 - p1;
		double p2 = in.nextInt();
		p2 *= 0.01;
		p2 = 1 - p2;
		double[] dp = new double[32];
		for(int i=0; i<32; i++){
			if(i==0 || i==15 || i== 16 || i==31) continue;
			dp[i] = 1;
		}
		for(int i=a; i<80; i++){
			double[] tmp = new double[32];
			for(int j=1; j<31; j++){
				tmp[j] = p1*dp[j]*((1.0-dp[j-1])*dp[j+1]+(1.0-dp[j+1])*dp[j-1]);
				tmp[j]+= p0*dp[j]*(1.0-dp[j-1])*(1.0-dp[j+1]);
				tmp[j]+= p2*dp[j]*dp[j-1]*dp[j+1];
//				tmp[j] = 1- tmp[j];
			}
			dp = tmp;
		}
		double res = 0;
		for(int i=0; i<32; i++){
			res += dp[i];
		}
		System.out.println(res);
	}
}


class MyComp implements Comparator<int[]>{
	public int compare(int[] a, int[] b) {
		return a[0] - b[0];
	}
}

class Reverse implements Comparator<Integer>{
	public int compare(Integer arg0, Integer arg1) {
		return arg1 - arg0;
	}
}

class Node implements Comparable<Node>{
	int id;
	List<Node> edge = new ArrayList<Node>();
//	List<Integer> cost = new ArrayList<Integer>();
	int sum;
	public Node(int id){
		this.id = id;
		sum = 100000000;
	}
	public void createEdge(Node node){
		edge.add(node);
//		cost.add(c);
	}
	@Override
	public int compareTo(Node o) {
		// TODO 自動生成されたメソッド・スタブ
		return sum - o.sum;
	}
}

class ContestWriter{
	private PrintWriter out;
	public ContestWriter(String filename) throws IOException{
		out = new PrintWriter(new BufferedWriter(new FileWriter(filename)));
	}
	
	public ContestWriter() throws IOException{
		out = new PrintWriter(System.out);
	}
	
	public void println(String str){
		out.println(str);
	}
	
	public void print(String str){
		out.print(str);
	}
	
	public void close(){
		out.close();
	}
}

class ContestScanner{
	private BufferedReader reader;
	private String[] line;
	private int idx;
	public ContestScanner() throws FileNotFoundException{
		reader = new BufferedReader(new InputStreamReader(System.in));
	}

	public ContestScanner(String filename) throws FileNotFoundException{
		reader = new BufferedReader(new InputStreamReader(new FileInputStream(filename)));
	}
	
	public String nextToken() throws IOException{
		if(line == null || line.length <= idx){
			line = reader.readLine().trim().split(" ");
			idx = 0;
		}
		return line[idx++];
	}
	public long nextLong() throws IOException, NumberFormatException{
		return Long.parseLong(nextToken());
	}
	public int nextInt() throws NumberFormatException, IOException{
		return (int)nextLong();
	}
	public double nextDouble() throws NumberFormatException, IOException{
		return Double.parseDouble(nextToken());
	}
}