#include<cstdio>
#include <iostream>
#include<algorithm>
#include<string>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<numeric>

using namespace std;
typedef long long ll;
typedef pair<int, int> Pr;

int N;
int A[17];
queue<int> q;

int main()
{
	cin >> N;
	for (int i = 0; i < N; i++) {
		cin >> A[i];
	}

	int ans,mi,mx;
	q.push(A[0]);
	for (int j = 1; j < N; j++) {
			for (int i = 0; i < pow(2,j-1); i++) {
				int a = q.front(); q.pop();
				mi = min(a + A[j], min(a - A[j], a*A[j]));
				mx = max(a + A[j], max(a - A[j], a*A[j]));
				if (a != 0) {
					mi = min(mi, a / A[j]);
					mx = max(mx, a / A[j]);
				}
				q.push(mi);
				q.push(mx);
				if (j == 1)break;
			}
	}
	cout << max(mx,mi) << endl;
	return 0;
}