#include <stdio.h>
#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000001



int main(){	
	int A;
	cin>>A;
	
	vector<double> p(3);
	rep(i,3){
		cin>>p[i];
		p[i] /= 100.0;
	}
	vector ps(1<<14,vector<double>(14));
	
	rep(i,1<<14){
		rep(j,14){
			int c = 0;
			if(j!=0){
				if(((i>>(j-1))&1)==0)c++;
			}
			if(j!=13){
				if(((i>>(j+1))&1)==0)c++;
			}
			ps[i][j] = p[c];
		}
	}
	
	vector<double> dp(1<<14,0.0);
	dp[0] = 1.0;
	
	rep(i,80-A){
		vector<double> ndp(1<<14,0.0);
		rep(j,1<<14){
			
			int S = 1<<14;
			S--;
			S ^= j;
			for(int T = S;true;T = (T-1)&S){
				double v = dp[j];
				rep(k,14){
					if((T>>k)&1)v *= ps[j][k];
					else if(((j>>k)&1)==0) v *= 1.0 - ps[j][k];
				}
				ndp[j|T] += v;
				
				if(T==0)break;
			}
			
		}
		swap(dp,ndp);
	}
	
	double ans = 0.0;
	rep(i,1<<14){
		ans += (14-__builtin_popcount(i)) * dp[i];
	}
	ans *= 2.0;
	cout<<fixed<<setprecision(10)<<ans<<endl;
	
	return 0;
	
}