#include<bits/stdc++.h>
using namespace std;
#define int long long
int solve_mx(int a, int num){
	int pl = num + a;
	int mi = num - a;
	int ml = num * a;
	int di;
	if(a == 0)di = -1e9;
	else di = num / a;
	return max(pl, max(mi, max(ml, di)));
}

int solve_mn(int a, int num){
	int pl = num + a;
	int mi = num - a;
	int ml = num * a;
	int di;
	if(a == 0)di = 1e9;
	else di = num / a;
	return min(pl, min(mi, min(ml, di)));
}


signed main(){
	int n;
	cin >> n;

	int mx, mn;
	int a;
	
	cin >> a;
	mx = a;
	mn = a;
		
	for(int i = 1; i < n; i++){
		cin >> a;
		int tmp1 = mx;
		mx = solve_mx(a, mx);
		int tmp = solve_mx(a, mn);
		mx = max(mx, tmp);

		mn = solve_mn(a, mn);
		tmp1 = solve_mn(a, tmp1);
		mn = min(mn, tmp1);
		//cout << mx << " " << mn << endl;
	}

	cout << mx << endl;
}