인프런 커뮤니티 질문&답변

n = int(input())
lst = [list(map(int, input().split())) for _ in range(n)]


maximum = 0

mid = n // 2

for i in range(mid+1):
    maximum += sum(lst[mid-i][i:n-i])

for i in range(1, mid+1):
    maximum += sum(lst[mid+i][i:n-i])

print(maximum)