import java.util.Scanner;

public class Main{
	public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		long N = scn.nextInt();
		long[] arr = new long[(int) N];
		int zero = 0;
		for (int i = 0; i < N; i++) {
			arr[i] = scn.nextLong();
			if (arr[i] == 0) {
				zero++;
			}
		}
		if (zero != 0) {
			System.out.println(0);
		} else {
			long ans = 1;
			boolean check = true;
			for (int i = 0; i < N; i++) {
				if (checklong(ans, arr[i]) && ans * arr[i] <= 1000000000000000000L) {
					ans = ans * arr[i];
				} else {
					check = false;
					System.out.println(-1);
					break;
				}
			}
			if (check) {
				System.out.println(ans);
			}
		}
	}

	public static boolean checklong(long a, long b) {
		long c = a * b;
		if ((c / (a)) == b) {
			return true;
		}
		return false;
	}
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz