### BUGGY CODE ###

import sys
sys.setrecursionlimit(4100000)

import math

import logging

logging.basicConfig(level=logging.DEBUG)

logger = logging.getLogger(__name__)


def resolve():
    # S = [x for x in sys.stdin.readline().split()][0]  # 文字列 一つ
    N = [int(x) for x in sys.stdin.readline().split()][0]  # int 一つ
    # N, D = [int(x) for x in sys.stdin.readline().split()]  # 複数int
    a_list = [int(x) for x in sys.stdin.readline().split()]  # 複数int

    # grid = [list(sys.stdin.readline().split()[0]) for _ in range(N)]  # 文字列grid
    # v_list = [int(sys.stdin.readline().split()[0]) for _ in range(N)]
    # grid = [[int(x) for x in sys.stdin.readline().split()]
    #         for _ in range(N)]  # int grid

    logger.debug('{}'.format([a_list]))
    b = 10**18

    a = 1
    for _a in a_list:
        a *= _a

    if a > b:
        print(-1)
    else:
        print(a)


if __name__ == "__main__":
    resolve()

# AtCoder Unit Test で自動生成できる, 最後のunittest.main は消す
# python -m unittest template/template.py で実行できる
# pypy3 -m unittest template/template.py で実行できる

import sys
from io import StringIO
import unittest


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)

    def test_入力例_1(self):
        input = """2
1000000000 1000000000"""
        output = """1000000000000000000"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """3
101 9901 999999000001"""
        output = """-1"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """31
4 1 5 9 2 6 5 3 5 8 9 7 9 3 2 3 8 4 6 2 6 4 3 3 8 3 2 7 9 5 0"""
        output = """0"""
        self.assertIO(input, output)


### FIXED CODE ###

import sys
sys.setrecursionlimit(4100000)

import math

import logging

logging.basicConfig(level=logging.DEBUG)

logger = logging.getLogger(__name__)


def resolve():
    # S = [x for x in sys.stdin.readline().split()][0]  # 文字列 一つ
    N = [int(x) for x in sys.stdin.readline().split()][0]  # int 一つ
    # N, D = [int(x) for x in sys.stdin.readline().split()]  # 複数int
    a_list = [int(x) for x in sys.stdin.readline().split()]  # 複数int

    # grid = [list(sys.stdin.readline().split()[0]) for _ in range(N)]  # 文字列grid
    # v_list = [int(sys.stdin.readline().split()[0]) for _ in range(N)]
    # grid = [[int(x) for x in sys.stdin.readline().split()]
    #         for _ in range(N)]  # int grid

    b = 10**18

    if 0 in a_list:
        print(0)
        return

    a = 1
    for _a in a_list:
        a *= _a
        if a > b:
            print(-1)
            return

    print(a)


if __name__ == "__main__":
    resolve()

# AtCoder Unit Test で自動生成できる, 最後のunittest.main は消す
# python -m unittest template/template.py で実行できる
# pypy3 -m unittest template/template.py で実行できる

import sys
from io import StringIO
import unittest


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)

    def test_入力例_1(self):
        input = """2
1000000000 1000000000"""
        output = """1000000000000000000"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """3
101 9901 999999000001"""
        output = """-1"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """31
4 1 5 9 2 6 5 3 5 8 9 7 9 3 2 3 8 4 6 2 6 4 3 3 8 3 2 7 9 5 0"""
        output = """0"""
        self.assertIO(input, output)