#include <algorithm>
#include <iostream>
#include <cstdio>
#include <map>
#include <numeric>
#include <cmath>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <complex>
#include <string.h>
#include <unordered_set>
#include <unordered_map>
#include <bitset>
#include <iomanip>
#include <sys/time.h>
#include <tuple>
#include <random>
using namespace std;

#define endl '\n'
#define ALL(v) (v).begin(), (v).end()
#define RALL(v) (v).rbegin(), (v).rend()
#define UNIQ(v) (v).erase(unique((v).begin(), (v).end()), (v).end())

typedef long long ll;
typedef long double ld;
typedef pair<int, int> P;
typedef complex<double> comp;
typedef vector< vector<ld> > matrix;
struct pairhash {
public:
    template<typename T, typename U>
    size_t operator()(const pair<T, U> &x) const {
	size_t seed = hash<T>()(x.first);
	return hash<U>()(x.second) + 0x9e3779b9 + (seed<<6) + (seed>>2);
    }
};
const int inf = 1e9 + 9;
const ll mod = 1e9 + 7;
const double eps = 1e-8;
const double pi = acos(-1);

int a;
double p[3];
double dp[15][22];

double calc(int k, int r) {
    if (r == 0) return k;
    if (dp[k][r] < 0) {
        if (k == 1) {
            dp[k][r] = (1.0-p[0]) * calc(k, r-1);
        } else {
            double res = 0.0;
            for (int i = 0; i < (1<<k); i++) {
                double q = 1.0;
                for (int j = 1; j < k-1; j++) q *= ((i>>j)&1 ? 1.0-p[2] : p[2]);
                q *= (i&1 ? 1.0-p[1] : p[1]);
                q *= ((i>>(k-1))&1 ? 1.0-p[1] : p[1]);
                int j = 0, c;
                while (j < k) {
                    if (!((i>>j)&1)) {
                        j++;
                        continue;
                    }
                    c = 0;
                    while (j+c<k && ((i>>(j+c))&1)) c++;
                    res += q * calc(c, r-1);
                    j += c;
                }
            }
            dp[k][r] = res;
        }
    }
    return dp[k][r];
}

double solve() {
    for (int i = 0; i < 15; i++) fill_n(dp[i], 22, -1.0);
    return calc(14, 80 - a) * 2;
}

void input() {
    cin >> a;
    for (int i = 0; i < 3; i++) {
        cin >> p[i];
        p[i] /= 100.0;
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(15);

    input();
    cout << solve() << endl;
}