Buggy python submission (verdict: Runtime Error):
#
# abc071 c
#
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 = """6
3 1 2 4 2 1"""
        output = """2"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """4
1 2 3 4"""
        output = """0"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """10
3 3 3 3 4 4 4 5 5 5"""
        output = """20"""
        self.assertIO(input, output)


def resolve():
    N = int(input())
    A = list(map(int, input().split()))

    Num = [0] * 10**9
    for a in A:
        Num[a-1] += 1

    l1 = l2 = 0
    for i in range(N-1, -1, -1):
        if l1 == 0:
            if Num[i] >= 2:
                l1 = i+1
                if Num[i] >= 4:
                    l2 = i+1
                    break
        else:
            if Num[i] >= 2:
                l2 = i+1
                break

    print(l1*l2)


if __name__ == "__main__":
    # unittest.main()
    resolve()


Fixed submission:
#
# abc071 c
#
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 = """6
3 1 2 4 2 1"""
        output = """2"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """4
1 2 3 4"""
        output = """0"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """10
3 3 3 3 4 4 4 5 5 5"""
        output = """20"""
        self.assertIO(input, output)


def resolve():
    N = int(input())
    A = list(map(int, input().split()))

    A.sort(reverse=True)
    l1 = l2 = 0
    for i in range(1, N):
        if l1 == 0:
            if A[i] == A[i-1]:
                l1 = A[i-1]
        else:
            if i < N-1 and A[i+1] == A[i]:
                l2 = A[i]
                break

    print(l1*l2)


if __name__ == "__main__":
    # unittest.main()
    resolve()

Buggy python submission (verdict: Runtime Error):
#
# abc071 c
#
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 = """6
3 1 2 4 2 1"""
        output = """2"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """4
1 2 3 4"""
        output = """0"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """10
3 3 3 3 4 4 4 5 5 5"""
        output = """20"""
        self.assertIO(input, output)


def resolve():
    N = int(input())
    A = list(map(int, input().split()))

    Num = [0] * N

    print(l1*l2)


if __name__ == "__main__":
    # unittest.main()
    resolve()


Fixed submission:
#
# abc071 c
#
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 = """6
3 1 2 4 2 1"""
        output = """2"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """4
1 2 3 4"""
        output = """0"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """10
3 3 3 3 4 4 4 5 5 5"""
        output = """20"""
        self.assertIO(input, output)


def resolve():
    N = int(input())
    A = list(map(int, input().split()))

    A.sort(reverse=True)
    l1 = l2 = 0
    for i in range(1, N):
        if l1 == 0:
            if A[i] == A[i-1]:
                l1 = A[i-1]
        else:
            if i < N-1 and A[i+1] == A[i]:
                l2 = A[i]
                break

    print(l1*l2)


if __name__ == "__main__":
    # unittest.main()
    resolve()

Buggy python submission (verdict: Runtime Error):
#
# abc071 c
#
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 = """6
3 1 2 4 2 1"""
        output = """2"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """4
1 2 3 4"""
        output = """0"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """10
3 3 3 3 4 4 4 5 5 5"""
        output = """20"""
        self.assertIO(input, output)


def resolve():
    N = int(input())
    A = list(map(int, input().split()))

    Num = [0] * N
    for a in A:
        Num[a-1] += 1

    l1 = l2 = 0
    print(l1*l2)


if __name__ == "__main__":
    # unittest.main()
    resolve()


Fixed submission:
#
# abc071 c
#
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 = """6
3 1 2 4 2 1"""
        output = """2"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """4
1 2 3 4"""
        output = """0"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """10
3 3 3 3 4 4 4 5 5 5"""
        output = """20"""
        self.assertIO(input, output)


def resolve():
    N = int(input())
    A = list(map(int, input().split()))

    A.sort(reverse=True)
    l1 = l2 = 0
    for i in range(1, N):
        if l1 == 0:
            if A[i] == A[i-1]:
                l1 = A[i-1]
        else:
            if i < N-1 and A[i+1] == A[i]:
                l2 = A[i]
                break

    print(l1*l2)


if __name__ == "__main__":
    # unittest.main()
    resolve()

Buggy python submission (verdict: Runtime Error):
#
# abc071 c
#
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 = """6
3 1 2 4 2 1"""
        output = """2"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """4
1 2 3 4"""
        output = """0"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """10
3 3 3 3 4 4 4 5 5 5"""
        output = """20"""
        self.assertIO(input, output)


def resolve():
    N = int(input())
    A = list(map(int, input().split()))

    Num = [0] * N
    for a in A:
        Num[a-1] += 1

    l1 = l2 = 0
    for i in range(N-1, -1, -1):
        if l1 == 0:
            if Num[i] >= 2:
                l1 = i+1
                if Num[i] >= 4:
                    l2 = i+1
                    break
        else:
            if Num[i] >= 2:
                l2 = i+1
                break

    print(l1*l2)


if __name__ == "__main__":
    # unittest.main()
    resolve()


Fixed submission:
#
# abc071 c
#
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 = """6
3 1 2 4 2 1"""
        output = """2"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """4
1 2 3 4"""
        output = """0"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """10
3 3 3 3 4 4 4 5 5 5"""
        output = """20"""
        self.assertIO(input, output)


def resolve():
    N = int(input())
    A = list(map(int, input().split()))

    A.sort(reverse=True)
    l1 = l2 = 0
    for i in range(1, N):
        if l1 == 0:
            if A[i] == A[i-1]:
                l1 = A[i-1]
        else:
            if i < N-1 and A[i+1] == A[i]:
                l2 = A[i]
                break

    print(l1*l2)


if __name__ == "__main__":
    # unittest.main()
    resolve()

Buggy python submission (verdict: Runtime Error):
#
# abc071 c
#
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 = """6
3 1 2 4 2 1"""
        output = """2"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """4
1 2 3 4"""
        output = """0"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """10
3 3 3 3 4 4 4 5 5 5"""
        output = """20"""
        self.assertIO(input, output)


def resolve():
    N = int(input())
    A = list(map(int, input().split()))

    Num = [0] * N
    for a in A:
        Num[a-1] += 1

    l1 = l2 = 0
    for i in range(len(Num)-1, -1, -1):
        if l1 == 0:
            if Num[i] >= 2:
                l1 = i+1
            if Num[i] >= 4:
                l2 = i+1
                break
        else:
            if Num[i] >= 2:
                l2 = i+1
                break

    print(l1*l2)


if __name__ == "__main__":
    # unittest.main()
    resolve()


Fixed submission:
#
# abc071 c
#
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 = """6
3 1 2 4 2 1"""
        output = """2"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """4
1 2 3 4"""
        output = """0"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """10
3 3 3 3 4 4 4 5 5 5"""
        output = """20"""
        self.assertIO(input, output)


def resolve():
    N = int(input())
    A = list(map(int, input().split()))

    A.sort(reverse=True)
    l1 = l2 = 0
    for i in range(1, N):
        if l1 == 0:
            if A[i] == A[i-1]:
                l1 = A[i-1]
        else:
            if i < N-1 and A[i+1] == A[i]:
                l2 = A[i]
                break

    print(l1*l2)


if __name__ == "__main__":
    # unittest.main()
    resolve()

Buggy python submission (verdict: Runtime Error):
#
# abc071 c
#
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 = """6
3 1 2 4 2 1"""
        output = """2"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """4
1 2 3 4"""
        output = """0"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """10
3 3 3 3 4 4 4 5 5 5"""
        output = """20"""
        self.assertIO(input, output)


def resolve():
    N = int(input())
    A = list(map(int, input().split()))

    Num = [0] * N
    for a in A:
        Num[a-1] += 1

    l1 = l2 = 0
    for i in range(len(Num)-1, -1, -1):
        if l1 == 0:
            if Num[i] >= 2:
                l1 = i+1
            if Num[i] >= 4:
                l2 = i+1
                break
        else:
            if Num[i] >= 2:
                l2 = i+1
                break

    print(l1*l2)


if __name__ == "__main__":
    # unittest.main()
    resolve()


Fixed submission:
#
# abc071 c
#
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 = """6
3 1 2 4 2 1"""
        output = """2"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """4
1 2 3 4"""
        output = """0"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """10
3 3 3 3 4 4 4 5 5 5"""
        output = """20"""
        self.assertIO(input, output)


def resolve():
    N = int(input())
    A = list(map(int, input().split()))

    A.sort(reverse=True)
    l1 = l2 = 0
    for i in range(1, N):
        if l1 == 0:
            if A[i] == A[i-1]:
                l1 = A[i-1]
        else:
            if i < N-1 and A[i+1] == A[i]:
                l2 = A[i]
                break

    print(l1*l2)


if __name__ == "__main__":
    # unittest.main()
    resolve()