import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) {
        FastReader input = new FastReader();
        int n = input.nextInt();
        long[] arr = new long[n];
        for(int i = 0;i < n;i++){
            arr[i] = input.nextLong();
        }
        Arrays.sort(arr);

        BigInteger a1 = BigInteger.valueOf(arr[0]);
        BigInteger k = new BigInteger("1000000000000000000");

        for(int i = 1;i < n;i++){
            BigInteger b1 = BigInteger.valueOf(arr[i]);
            a1 = a1.multiply(b1);
            if(a1.compareTo(k) == 1){

                System.out.println(-1);
                return;
            }
        }
        System.out.println(a1);
    }
    static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;

        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt()
        {
            return Integer.parseInt(next());
        }

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.math.BigInteger; BigInteger java.math import java.util.Arrays; Arrays java.util import java.util.StringTokenizer; StringTokenizer java.util public class Main {
    public static void main(String[] args) {
        FastReader input = new FastReader();
        int n = input.nextInt();
        long[] arr = new long[n];
        for(int i = 0;i < n;i++){
            arr[i] = input.nextLong();
        }
        Arrays.sort(arr);

        BigInteger a1 = BigInteger.valueOf(arr[0]);
        BigInteger k = new BigInteger("1000000000000000000");

        for(int i = 1;i < n;i++){
            BigInteger b1 = BigInteger.valueOf(arr[i]);
            a1 = a1.multiply(b1);
            if(a1.compareTo(k) == 1){

                System.out.println(-1);
                return;
            }
        }
        System.out.println(a1);
    }
    static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;

        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt()
        {
            return Integer.parseInt(next());
        }

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
} Main public static void main(String[] args) {
        FastReader input = new FastReader();
        int n = input.nextInt();
        long[] arr = new long[n];
        for(int i = 0;i < n;i++){
            arr[i] = input.nextLong();
        }
        Arrays.sort(arr);

        BigInteger a1 = BigInteger.valueOf(arr[0]);
        BigInteger k = new BigInteger("1000000000000000000");

        for(int i = 1;i < n;i++){
            BigInteger b1 = BigInteger.valueOf(arr[i]);
            a1 = a1.multiply(b1);
            if(a1.compareTo(k) == 1){

                System.out.println(-1);
                return;
            }
        }
        System.out.println(a1);
    } main {
        FastReader input = new FastReader();
        int n = input.nextInt();
        long[] arr = new long[n];
        for(int i = 0;i < n;i++){
            arr[i] = input.nextLong();
        }
        Arrays.sort(arr);

        BigInteger a1 = BigInteger.valueOf(arr[0]);
        BigInteger k = new BigInteger("1000000000000000000");

        for(int i = 1;i < n;i++){
            BigInteger b1 = BigInteger.valueOf(arr[i]);
            a1 = a1.multiply(b1);
            if(a1.compareTo(k) == 1){

                System.out.println(-1);
                return;
            }
        }
        System.out.println(a1);
    } FastReader input = new FastReader(); input new FastReader() int n = input.nextInt(); n input.nextInt() input.nextInt input long[] arr = new long[n]; arr new long[n] n for(int i = 0;i < n;i++){
            arr[i] = input.nextLong();
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            arr[i] = input.nextLong();
        } {
            arr[i] = input.nextLong();
        } arr[i] = input.nextLong() arr[i] arr i input.nextLong() input.nextLong input Arrays.sort(arr) Arrays.sort Arrays arr BigInteger a1 = BigInteger.valueOf(arr[0]); a1 BigInteger.valueOf(arr[0]) BigInteger.valueOf BigInteger arr[0] arr 0 BigInteger k = new BigInteger("1000000000000000000"); k new BigInteger("1000000000000000000") for(int i = 1;i < n;i++){
            BigInteger b1 = BigInteger.valueOf(arr[i]);
            a1 = a1.multiply(b1);
            if(a1.compareTo(k) == 1){

                System.out.println(-1);
                return;
            }
        } int i = 1; int i = 1; i 1 i < n i n i++ i++ i {
            BigInteger b1 = BigInteger.valueOf(arr[i]);
            a1 = a1.multiply(b1);
            if(a1.compareTo(k) == 1){

                System.out.println(-1);
                return;
            }
        } {
            BigInteger b1 = BigInteger.valueOf(arr[i]);
            a1 = a1.multiply(b1);
            if(a1.compareTo(k) == 1){

                System.out.println(-1);
                return;
            }
        } BigInteger b1 = BigInteger.valueOf(arr[i]); b1 BigInteger.valueOf(arr[i]) BigInteger.valueOf BigInteger arr[i] arr i a1 = a1.multiply(b1) a1 a1.multiply(b1) a1.multiply a1 b1 if(a1.compareTo(k) == 1){

                System.out.println(-1);
                return;
            } a1.compareTo(k) == 1 a1.compareTo(k) a1.compareTo a1 k 1 {

                System.out.println(-1);
                return;
            } System.out.println(-1) System.out.println System.out System System.out -1 1 return; System.out.println(a1) System.out.println System.out System System.out a1 String[] args args static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;

        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt()
        {
            return Integer.parseInt(next());
        }

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    } FastReader BufferedReader br; br StringTokenizer st; st public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        } FastReader {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        } br = new BufferedReader(new
                    InputStreamReader(System.in)) br new BufferedReader(new
                    InputStreamReader(System.in)) String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } next {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            } try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                } catch (IOException e)
                {
                    e.printStackTrace();
                } IOException e {
                    e.printStackTrace();
                } e.printStackTrace() e.printStackTrace e {
                    st = new StringTokenizer(br.readLine());
                } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt()
        {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong()
        {
            return Long.parseLong(next());
        } nextLong {
            return Long.parseLong(next());
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble()
        {
            return Double.parseDouble(next());
        } nextDouble {
            return Double.parseDouble(next());
        } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        } nextLine {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        } String str = ""; str "" try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            } catch (IOException e)
            {
                e.printStackTrace();
            } IOException e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                str = br.readLine();
            } str = br.readLine() str br.readLine() br.readLine br return str; str public class Main {
    public static void main(String[] args) {
        FastReader input = new FastReader();
        int n = input.nextInt();
        long[] arr = new long[n];
        for(int i = 0;i < n;i++){
            arr[i] = input.nextLong();
        }
        Arrays.sort(arr);

        BigInteger a1 = BigInteger.valueOf(arr[0]);
        BigInteger k = new BigInteger("1000000000000000000");

        for(int i = 1;i < n;i++){
            BigInteger b1 = BigInteger.valueOf(arr[i]);
            a1 = a1.multiply(b1);
            if(a1.compareTo(k) == 1){

                System.out.println(-1);
                return;
            }
        }
        System.out.println(a1);
    }
    static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;

        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt()
        {
            return Integer.parseInt(next());
        }

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
} public class Main {
    public static void main(String[] args) {
        FastReader input = new FastReader();
        int n = input.nextInt();
        long[] arr = new long[n];
        for(int i = 0;i < n;i++){
            arr[i] = input.nextLong();
        }
        Arrays.sort(arr);

        BigInteger a1 = BigInteger.valueOf(arr[0]);
        BigInteger k = new BigInteger("1000000000000000000");

        for(int i = 1;i < n;i++){
            BigInteger b1 = BigInteger.valueOf(arr[i]);
            a1 = a1.multiply(b1);
            if(a1.compareTo(k) == 1){

                System.out.println(-1);
                return;
            }
        }
        System.out.println(a1);
    }
    static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;

        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt()
        {
            return Integer.parseInt(next());
        }

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) {
        FastReader input = new FastReader();
        int n = input.nextInt();
        long[] arr = new long[n];
        for(int i = 0;i < n;i++){
            arr[i] = input.nextLong();
        }
        Arrays.sort(arr);

        BigInteger a1 = BigInteger.valueOf(arr[0]);
        BigInteger k = new BigInteger("1000000000000000000");

        for(int i = 1;i < n;i++){
            BigInteger b1 = BigInteger.valueOf(arr[i]);
            a1 = a1.multiply(b1);
            if(a1.compareTo(k) == 1){

                System.out.println(-1);
                return;
            }
        }
        System.out.println(a1);
    }
    static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;

        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt()
        {
            return Integer.parseInt(next());
        }

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
}
