#include <bits/stdc++.h>
using namespace std;

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int A; cin >> A;
    double p0,p1,p2; cin >> p0 >> p1 >> p2;
    p0 /= 100,p1 /= 100,p2 /= 100;

    int n = 14,n2 = 1<<n;
    vector<double> dp(n2);
    dp.at(n2-1) = 2;
    while(A < 80){
        vector<double> next(n2);
        for(int i=0; i<n2; i++){
            if(dp.at(i) == 0) continue;
            double d = dp.at(i);
            for(int k=i; ; k=(k-1)&i){
                double mul = 1;
                for(int p=0; p<n; p++) if(i&(1<<p)){
                    int ok = (i>>(p+1))&1;
                    if(p) ok += (i>>(p-1))&1;
                    if(k&(1<<p)){
                        if(ok == 0) mul *= (1-p0);
                        else if(ok == 1) mul *= (1-p1);
                        else mul *= (1-p2);
                    }
                    else{
                        if(ok == 0) mul *= p0;
                        else if(ok == 1) mul *= p1;
                        else mul *= p2;
                    }
                }
                next.at(k) += d*mul;
                if(k == 0) break;
            }
        }

        swap(dp,next),A++;
    }
    double answer = 0;
    for(int i=0; i<n2; i++) answer += __popcount(i)*dp.at(i);
    cout << fixed << setprecision(20) << answer << endl;
}