from heapq import heapify, heappush, heappop
n = int(input())
A = sorted(list(map(int,input().split())))
if n == 1 or n == 2:
    A.append(1)
    print(A[0]*A[1])
    exit()
if n % 2:
    print(1)
    exit()


num = A[0]*A[1]
print(num)