#include <bits/stdc++.h>
#define rep(i, a) for (int i = (int)0; i < (int)a; ++i)
#define rrep(i, a) for (int i = (int)a - 1; i >= 0; --i)
#define REP(i, a, b) for (int i = (int)a; i < (int)b; ++i)
#define RREP(i, a, b) for (int i = (int)a - 1; i >= b; --i)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
using ll = long long;
constexpr ll mod = 1e9 + 7;
constexpr ll INF = 1LL << 60;

template <class T>
inline bool chmin(T &a, T b)
{
	if (a > b)
	{
		a = b;
		return true;
	}
	return false;
}
template <class T>
inline bool chmax(T &a, T b)
{
	if (a < b)
	{
		a = b;
		return true;
	}
	return false;
}

ll gcd(ll n, ll m)
{
	ll tmp;
	while (m != 0)
	{
		tmp = n % m;
		n = m;
		m = tmp;
	}
	return n;
}

ll lcm(ll n, ll m)
{
	return abs(n) / gcd(n, m) * abs(m); //gl=xy
}

using namespace std;

void solve()
{
	int n;
	cin>>n;
	vector<ll>a(n);
	rep(i,n)cin>>a[i];
	vector<vector<vector<ll>>>dp(n+1,vector<vector<ll>>(4,vector<ll>(2)));
	rep(i,n+1)rep(j,4){dp[i][j][0]=-INF;dp[i][j][1]=INF;}
	rep(i,4)rep(j,2)dp[0][i][j]=a[0];
	rep(i,n-1){
		if(a[i+1]!=0){
			rep(j,4){
				rep(k,2){
					if(dp[i][j][k]==-INF)continue;
					if(dp[i][j][k]==INF)continue;
					chmax(dp[i+1][3][0],dp[i][j][k]/a[i+1]);
					chmin(dp[i+1][3][1],dp[i][j][k]/a[i+1]);
				}
			}
		}
		rep(j,4){
			rep(k,2){
				if(dp[i][j][k]==-INF)continue;
				if(dp[i][j][k]==INF)continue;
				chmax(dp[i+1][0][0],dp[i][j][k]+a[i+1]);
				chmax(dp[i+1][1][0],dp[i][j][k]-a[i+1]);
				chmax(dp[i+1][2][0],dp[i][j][k]*a[i+1]);
				chmin(dp[i+1][0][1],dp[i][j][k]+a[i+1]);
				chmin(dp[i+1][1][1],dp[i][j][k]-a[i+1]);
				chmin(dp[i+1][2][1],dp[i][j][k]*a[i+1]);
			}
		}
	}
	ll ans=-INF;
	rep(i,4)if(dp[n-1][i][0]!=INF)chmax(ans,dp[n-1][i][0]);
	cout<<ans<<"\n";
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout << fixed << setprecision(15);
	solve();
	return 0;
}