n = int(input())
z = []
h = 1

for k in range(0, n):
    x = int(input())
    z.append(x)

for i in range(0, len(z)):
    for j in range(0, len(z)):
        if abs(i - j) >= 6:
            r = z[i] * z[j]
            if r % 2 != 0 and r < h * 10**6:
                h = r

print(h)