package javacode;

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class yukicoder2 {

	public static void main(String args[]){

		Scanner cin = new Scanner(System.in);

		int target = cin.nextInt();
		int tmp[] =new int[target];
		List <Integer> small = new ArrayList<Integer>();
		int result=1;
		int sum=0;

		for(int i=0;i<target;i++){
			tmp[i] = Math.abs(cin.nextInt());
			if(tmp[i]<2){
				small.add(i);
			}
		}
		if(small.size()==0){
			for(int j=0;j<target;j++){
				result *= tmp[j];
			}
		}else{
			for(int k=0;k<small.size();k++){
				sum +=tmp[small.get(k)];
			}
			for(int l=0;l<target;l++){
				if(!small.contains(l)){
					result *= tmp[l];
				}
			}
			result += sum;
		}
		System.out.println(result);
	}
}