#include<bits/stdc++.h>
using namespace std;
#ifdef LOCAL_DEBUG
  #include "LOCAL_DEBUG.hpp"
#endif
#define int long long
const int INF = 1LL << 60;

signed main(){

  int n; cin >> n;
  vector<int> a(n);
  for(int i = 0; i < n; i++){
    cin >> a[i];
  }

  int ans = 0;
  for(int i = 0; i < 1 << n; i++){
    vector<int> dp(100, 0);
    for(int j = 0; j < n; j++){
      if(j > 0 && i >> j & 1){
        dp[j+1] = dp[j] - a[j];
      }else {
        dp[j+1] = max(dp[j+1], dp[j] + a[j]);
        dp[j+1] = max(dp[j+1], dp[j] * a[j]);
      }
    }
    ans = max(ans, dp[n]);
  }
  cout << ans << endl;

  return 0;
}