import java.util.Scanner;

public class Main {

	static int target;
	public static void main(String argas[]){

		Scanner cin = new Scanner(System.in);

		target = cin.nextInt();
		int list[] = new int[target];

		for(int i=0;i<target;i++){
			list[i] = cin.nextInt();
		}
		cin.close();
		System.out.println(dfs(1,list[0],list));
	}

	static int dfs(int count,int sum,int array[]){
		if(count==target-1){
			return Math.max(sum*array[count], Math.max(sum+array[count],sum-array[count]));
		}else{
			return Math.max(dfs(count+1,sum*array[count],array), Math.max(dfs(count+1,sum+array[count],array), dfs(count+1,sum-array[count],array)));
		}
	}

}