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

int main() {
    int A, N;
    double P[3];
    cin >> A >> P[0] >> P[1] >> P[2];
    N = 80 - A;
    for (int i = 0; i < 3; i++) {
        P[i] /= 100;
    }

    double dp[2][1 << 14] = {};
    int now = 0, nxt = 1;
    dp[now][(1 << 14) - 1] = 1;

    auto prob = [&](int bit, int mask) {
        double ret = 1;
        for (int x = 0; x < 14; x++) {
            int cnt = 0;
            if (x != 0 && (bit & (1 << (x - 1))))
                cnt++;
            if (x != 13 && (bit & (1 << (x + 1))))
                cnt++;
            if (bit & (1 << x) && !(mask & (1 << x)))
                ret *= P[cnt];
            else if (bit & (1 << x) && (mask & (1 << x)))
                ret *= 1 - P[cnt];
        }
        return ret;
    };

    while (N--) {
        for (int bit = 0; bit < (1 << 14); bit++) {
            dp[nxt][bit] = 0;
        }
        for (int bit = 0; bit < (1 << 14); bit++) {
            for (int mask = bit; mask >= 0; mask--) {
                mask &= bit;
                dp[nxt][mask] += dp[now][bit] * prob(bit, mask);
            }
        }
        swap(now, nxt);
    }

    double ans = 0;
    for (int bit = 0; bit < (1 << 14); bit++) {
        ans += dp[now][bit] * __builtin_popcount(bit);
    }

    cout << fixed << setprecision(10) << ans * 2 << endl;
}