N = int(input())
_A = list(input().split())
if len(_A) != 1:
    print('"assert"')
else:
    A = sorted([int(_A[0])] + [int(input()) for _ in range(N-1)], reverse=True)
    print(A[0] + A[2] if A[1] != A[2] else A[1] + A[2])