H, W = map(int, input().split())
A = [list(map(int, input().split())) for i in range(H)]
B = [0 for i in range(H)]
C = [0 for i in range(W)]
for i in range(H):
    for j in range(W):
        C[j] += A[i][j]
        B[i] += A[i][j]
ans = -float('inf')
if H >= 2:
    ans = max(sum(sorted(B)[-2:]), ans)
if W >= 2:
    ans = max(sum(sorted(C)[-2:]), ans)
for i in range(H):
    for j in range(W):
        ans = max(C[j] + B[i] - A[i][j], ans)
print(ans)