m, n = map(int, input().split()) a = [] for i in range(m): b = list(map(int, input().split())) a.append(b) ans = 0 for i in range(m): for j in range(n): if i == 0 or j == 0 or i == m - 1 or j == n - 1: ans += a[i][j] print(ans)