#include <bits/stdc++.h>
#define GET_MACRO(a, b, c, NAME, ...) NAME
#define rep(...) GET_MACRO(__VA_ARGS__, rep3, rep2)(__VA_ARGS__)
#define rep2(i, a) rep3 (i, 0, a)
#define rep3(i, a, b) for (int i = (a); i < (b); i++)
#define repr(...) GET_MACRO(__VA_ARGS__, repr3, repr2)(__VA_ARGS__)
#define repr2(i, a) repr3 (i, 0, a)
#define repr3(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define chmin(a, b) ((b) < a && (a = (b), true))
#define chmax(a, b) (a < (b) && (a = (b), true))
using namespace std;
typedef long long ll;

double dp[100][100];
double P[3];

double f(int y, int n) {
	if (y == 0) return n;
	if (n == 0) return 0;
	if (dp[y][n] >= 0) return dp[y][n];

	double res = 0;
	rep (i, 1 << n) {
		double p = 1;
		rep (j, n) {
			int num = 2;
			if (j == 0) num--;
			if (j == n - 1) num--;
			if (i & 1 << j) {
				p *= 1 - P[num];
			} else {
				p *= P[num];
			}
		}
		double sum = 0;
		int j = 0;
		while (j < n) {
			int k = j;
			if (~i & 1 << k) {
				j++;
				continue;
			}
			while (k < n && (i & 1 << k)) k++;
			sum += f(y - 1, k - j);
			j = k;
		}
		res += sum * p;
	}	
	return dp[y][n] = res;
}

int main() {
	int A;
	cin >> A;
	rep (i, 3) cin >> P[i];
	rep (i, 3) P[i] /= 100;
	rep (i, 100) rep (j, 100) dp[i][j] = -1;
	double ans = f(80 - A, 14) * 2;
	printf("%.20f\n", ans);
	return 0;
}