N = int(input())

As = []
for _ in range(N):
    A = input()
    if ' ' in A:
        print('"assert"')
        break
    A = int(A)
    if len(As) < 3:
        As.append(A)
        As.sort()
    else:
        for i in range(len(As)):
            if As[i] < A:
                As.insert(i, A)
                As.pop()
else:
    As = sorted(As, reverse=True)
    if len(As) == len(set(As)):
        print(As[0] + As[2])
    else:
        print(As[1] + As[2])