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

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> ii;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef vector<ii> vii;

#define x first
#define y second
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(), (v).end()

const ld PI = acos((ld) -1);

void run() {
	ll n;
	cin >> n;
	ld res = 0;
	for (ll i = 0; i < n; i++) {
		ld c;
		cin >> c;
		res += c*c*c;
	}
	cout << pow(res, 1./3) << endl;
}

signed main() {
    ios_base::sync_with_stdio(false); cin.tie(0);
	cout << fixed << setprecision(20);
    run();
    return 0;
}