#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n;
	cin >> n;
	vector<ll> a(n);
	for (int i = 0; i < n; i++) cin >> a[i];
	set<ll> b;
	b.insert(a[0]);
	for (int i = 1; i < n; i++) {
		set<ll> c(b);
		bool flag = (a[i] != 0);
		for (ll x : c) {
			b.insert(x * a[i]);
			b.insert(x + a[i]);
			b.insert(x - a[i]);
			if (flag) b.insert(x / a[i]);
		}
	}
	ll ans = -1e9;
	for (ll x : b) ans = max(ans, x);
	cout << ans << endl;
	return 0;
}