#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 mask, double dp[YEAR][MASK]) {
    double &ret = dp[year][mask];
    if (ret > -0.5) return ret;

    if (mask == 0) {
        return 0;
    }
    
    if (year == limit) {
        return ret = __builtin_popcount(mask);
    }
    
    ret = 0;
    
    for (int nexMask = mask; nexMask; nexMask = (nexMask - 1) & mask) {
        
        double mul = 1;
        for (int i = 0; i < TEETH; ++i) {
            if (!(mask & (1 << i)))
                continue;

            int nMissing = 0;
            nMissing += (i == 0         || !(mask & (1 << (i - 1))));
            nMissing += (i == TEETH - 1 || !(mask & (1 << (i + 1))));
            
            if (nexMask & (1 << i)) {
                mul *= 1 - p[nMissing];
            }
            else {
                mul *= p[nMissing];
            }
        }

        ret += mul * rec(year + 1, nexMask, dp);
    }

    return ret;
}


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


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