# No.851 テストケース
n = int(input())
a = []

tmp = input()

if tmp.count(' ') > 0:
    print('\"assert\"')
else:
    a.append(int(tmp))

    for i in range(1, n):
        a.append(int(input()))
    
    total_twos = [a[0] + a[1], a[1] + a[2], a[2] + a[0]]

    if total_twos.count(max(total_twos)) > 1:
        print(min(total_twos))
    elif total_twos.count(min(total_twos)) > 1:
        print(min(total_twos))
    else:
        for j in total_twos:
            if j != min(total_twos) and j != max(total_twos):
                print(j)
                break