#pragma GCC optimizer("Ofast")
#pragma GCC target("avx2")
#include <bits/stdc++.h>
#define int long long 
#define ld long double
#define ull unsigned long long 
#define fr first
#define fi first
#define sc second
#define se second
#define all(x) x.begin(), x.end()
#define pii pair<int,int>
using namespace std;

#ifndef fireball
#define tofu ios::sync_with_stdio(0); cin.tie(0);
#else
#define tofu freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);
#endif 

void db() {cout << '\n';}
template <typename T, typename ...U> void db(T a, U ...b) {cout << a << ' ', db(b...);}

const ld pi = acos(-1);

signed main(){
    tofu;
    
    int n; cin >> n;
    ld e[n];
    for(int i = 0; i < n; ++i){
        cin >> e[i];
        e[i] = e[i] * e[i];
    }

    auto check = [&](ld m){
        ld sum = 0.0;
        m = m * m * 2;
        for(int i = 0; i < n; ++i){
            ld th = acos(1.0 - (e[i] / m));
            sum += th;
        }
        //db(m, sum);
        return (2 * pi) >= sum;
    };

    ld l = 0.0, r = 10000000.0, ans = 10000000.0;
    int cnt = 100;
    while(cnt--){
        ld m = (l + r) / 2.0;
        if(check(m)){
            ans = m;
            r = m;
        }
        else l = m;
    }
    cout << fixed << setprecision(10) << ans << endl;
}