N = int(input())

input_list = []
for i in range(N):
    n = input()
    comp = n.split()
    if len(comp) == 3:
        break
    else:
        input_list.append(int(n))

if len(input_list) == 3:
    sums = [sum(input_list[:2]),sum(input_list[1:3]),input_list[0]+input_list[-1]]
    sums.sort()
    print(sums[1])
else:
    print('assert')