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

int main(){
    int A;
    vector<int> p(3);
    cin >> A >> p[0] >> p[1] >> p[2];
    vector<vector<double>> dp(81,vector<double>(1<<14));
    dp[A][(1 << 14) - 1] = 1;
    auto f = [&](int S, int T){
        double res = 1;
        for(int j = 0; j < 14; j++){
            if(~S >> j & 1)continue;
            int cnt = 0;
            cnt += ((S >> j + 1) & 1);
            cnt += (j >= 1 &&((S >> j - 1)& 1));
            res *= (T >> j & 1 ? 100 - p[cnt] : p[cnt]) / 100.0;
        }
        return res;
    };
    for(int i = A; i < 80; i++){
        for(int j = 0; j < (1 << 14); j++){
            if(j == 0){
                dp[i + 1][j] += dp[i][j];
                continue;
            }
            for(int k = (j - 1) & j; k > 0; k = (k - 1) & j){
                dp[i + 1][k] += f(j, k) * dp[i][j];
            }
            dp[i + 1][j] += f(j, j) * dp[i][j];
            dp[i + 1][0] += f(j, 0) * dp[i][j];
        }
    }
    vector<double> fp(15);
    for(int j = 0; j < (1 << 14); j++){
        fp[__builtin_popcount(j)] += dp[80][j];
    }
    double ans = 0;
    for(int j = 0; j < 15; j++){
        for(int k = 0; k < 15; k++){
            ans += (j + k) * fp[j] * fp[k];
        }
    }
    printf("%.15lf\n",ans);
}