N = input()
A1_wk = input()
A1_list = A1_wk.split()

if len(A1_list) > 1:
    print("\"assert\"")
else:
    A1 = int(A1_list[0])
    A2 = int(input())
    A3 = int(input())
    ans_list = [A1+A2 , A2+A3 , A1+A3]
    ans_list.sort()
    if ans_list[1] == ans_list[2]:
        print(ans_list[0])
    else:
        print(ans_list[1])