S = 6
N = int(input())
a = [int(input()) for i in range(S)]

min_e = 10**4
min_pr = 10**7

for i in range(S, N):
	inp = int(input())
	min_e = min(min_e, a[0])
	min_pr = min(min_pr, min_e*inp)

	del a[0]
	a.append(inp)

print(min_pr)