#include<iostream>
#include<cstdio>
using namespace std;
const int YEAR = 21;
const int TEETH = 14;
const int MASK = 1 << TEETH;


int limit;
double p[3];

void read() {
    int age;
    cin >> age;

    limit = 80 - age;
    
    int pint0, pint1, pint2;
    cin >> pint0 >> pint1 >> pint2;
    
    p[2] = pint0 * 0.01;
    p[1] = pint1 * 0.01;
    p[0] = pint2 * 0.01;
}


double rec(int year, int nth, bool preExist, int mask, double dp[YEAR][TEETH][2][MASK]) {
    double &ret = dp[year][nth][preExist][mask];
    if (ret > -0.5) return ret;
    
    if (year == limit) {
        return ret = __builtin_popcount(mask);
    }

    if (nth == TEETH)
        return ret = rec(year + 1, 0, 0, mask, dp);

    if (!(mask & (1 << nth)))
        return ret = rec(year, nth + 1, 0, mask, dp);

    int nMissing = 0;
    nMissing += (nth == 0         || !preExist);
    nMissing += (nth == TEETH - 1 || !(mask & (1 << (nth + 1))));
    
    ret = 0;
    ret +=       p[nMissing] * rec(year, nth + 1, 1, mask & ~(1 << nth), dp);
    ret += (1 - p[nMissing]) * rec(year, nth + 1, 1, mask              , dp);
    
    return ret;
}


void work() {
    static double dp[YEAR][TEETH][2][MASK];
    for (int i = 0; i < YEAR; ++i)
        for (int j = 0; j < TEETH; ++j)
            for (int k = 0; k < 2; ++k)
                for (int l = 0; l < MASK; ++l)
                    dp[i][j][k][l] = -1;
    
    printf("%.10lf\n", rec(0, 0, 0, (1 << TEETH) - 1, dp) * 2);
}


int main() {
    read();
    work();
    return 0;
}