Buggy python submission (verdict: Runtime Error):
import math

n = int(input())
a = list(map(int, input().split()))
print(solution(n, a))  
gcd_left = [0]
gcd_right = [0]
for i in range(n):
    gcd_left.append(math.gcd(gcd_left[i], a[i]))
    # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
    # 要は右端から順にgcdを求めている
    gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

ans = []
for i in range(n):
    ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))


print(max(ans))

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Buggy python submission (verdict: Runtime Error):
import math

n = int(input())
a = list(map(int, input().split()))
print(solution(n, a))  
gcd_left = [0]
gcd_right = [0]
for i in range(n):
    gcd_left.append(math.gcd(gcd_left[i], a[i]))
    # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
    # 要は右端から順にgcdを求めている
    gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

ans = []
for i in range(n):
    ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))


return max(ans)

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Buggy python submission (verdict: Runtime Error):
import math


def main():
    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))  
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(math.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)

if __name__ == '__main__':
  
    main()

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Buggy python submission (verdict: Runtime Error):
import math


def main():
  
	n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))  
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(math.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)

if __name__ == '__main__':
  
    main()

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Buggy python submission (verdict: Runtime Error):
import math


def main():
	n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))  
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(math.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)

main()

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Buggy python submission (verdict: Runtime Error):
import math


def main():
	n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))  
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(math.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)

if __name__ == '__main__':
  
    main()

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Buggy python submission (verdict: Runtime Error):
import unittest
import math


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(math.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)


def main():
    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))


main()

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Buggy python submission (verdict: Runtime Error):
import unittest
import math


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(math.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)


def main():
    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))


if __name__ == '__main__':
  
    main()
    unittest.main()

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Buggy python submission (verdict: Runtime Error):
import math

def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(math.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


def main():
    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))


if __name__ == '__main__':
    main()

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Buggy python submission (verdict: Runtime Error):
import unittest
import math


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(math.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)


def main():
    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))


if __name__ == '__main__':
    main()

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Buggy python submission (verdict: Runtime Error):
import math

def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(math.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))
        
    return max(ans)

if __name__ == '__main__':
    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Buggy python submission (verdict: Runtime Error):
import unittest
import math


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(math.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)

if __name__ == '__main__':
    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Buggy python submission (verdict: Runtime Error):
import unittest
import math


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(math.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)


if __name__ == '__main__':
    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Buggy python submission (verdict: Runtime Error):
import unittest
import math


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(math.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(math.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(math.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)


if __name__ == '__main__':
    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()

Fixed submission:
import unittest
import fractions


def solution(n, a):
    gcd_left = [0]
    gcd_right = [0]
    for i in range(n):
        gcd_left.append(fractions.gcd(gcd_left[i], a[i]))
        # 順に(0とa[-1]), (a[-1]とa[-2]),...の比較
        # 要は右端から順にgcdを求めている
        gcd_right.append(fractions.gcd(gcd_right[i], a[-(i + 1)]))

    gcd_right = gcd_right[::-1]  # gcd_right[i]がi番目以降のgcdとなるように反転

    ans = []
    for i in range(n):
        ans.append(fractions.gcd(gcd_left[i], gcd_right[i + 1]))


    return max(ans)


class MyTestCase(unittest.TestCase):
    def test1(self):
        self.assertEqual(solution(3, [7, 6, 8]), 2)

    def test2(self):
        self.assertEqual(solution(3, [12, 15, 18]), 6)

    def test3(self):
        self.assertEqual(solution(2, [1000000000, 1000000000]), 1000000000)




if __name__ == '__main__':

    n = int(input())
    a = list(map(int, input().split()))
    print(solution(n, a))

    unittest.main()