input()
buf=input()
if len(buf.split())==3:
    print('assert')
else:
    input_lines=[buf]
    for i in range(2):
        input_lines.append(input())
    numbers=list(map(int,input_lines))
    numbers.sort()
    ans = numbers[0]*2 if numbers[0]==numbers[1] else numbers[0]+numbers[2]
    print(ans)