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

if len(a) == 3:
    print("\"assert\"")

else:
    for _ in range(2):
        a.append(int(input()))

    nums = set()
    for i in range(3):
        for j in range(i + 1, 3):
            nums.add(a[i] + a[j])

    ans = sorted(nums)[-2]
    print(ans)