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

typedef long long ll;
typedef pair<int, int> ii;

const int ms = 105;

long double dp[ms][ms][ms];
bool vis[ms][ms][ms];
int n;
long double a[ms];

long double solve(int on, int have, int acc){
    long double &x = dp[on][have][acc];
    if(vis[on][have][acc]) return x;

    vis[on][have][acc] = true;

    if(on == n){
        if(acc == 0) return x = 0;
        if(acc == have) return x = acc;
        return x = powl(acc, acc/(long double) have);
    }

    x = a[on] * solve(on + 1, have + 1, acc + 1) + (1-a[on]) * solve(on + 1, have + 1, acc);
    x = max(x, solve(on + 1, have, acc));
    return x;
}

int main () {
    ios::sync_with_stdio(0); cin.tie(0);
    cin >> n;
    cout << fixed << setprecision(10);
    for(int i = 0; i < n; ++i){
        cin >> a[i];
        a[i] /= 100;
    }
    sort(a, a + n, greater<int>());
    cout << solve(0, 0, 0) << '\n';
}