import java.util.*;

public class Main {
 	public static void main (String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		long result = 0;
		for (int i = 0; i < n; i++) {
		    int x = Math.abs(sc.nextInt());
		    if (x <= 1 || result == 0) {
		        result += x;
		    } else {
		        result *= x;
		    }
		}
		System.out.println(result);
	}
}