import sys
input = sys.stdin.readline

from collections import Counter

H,W=map(int,input().split())

A=[list(map(int,input().split())) for i in range(H)]

T=Counter()
Y=Counter()
P=Counter()
M=Counter()

for i in range(H):
    for j in range(W):
        T[i]+=A[i][j]
        Y[j]+=A[i][j]
        P[i+j]+=A[i][j]
        M[i-j]+=A[i][j]

ANS=0

for i in T:
    for j in T:
        if i==j:
            continue
        ANS=max(ANS,T[i]+T[j])

for i in Y:
    for j in Y:
        if i==j:
            continue
        ANS=max(ANS,Y[i]+Y[j])

for i in P:
    for j in P:
        if i==j:
            continue
        ANS=max(ANS,P[i]+P[j])

for i in M:
    for j in M:
        if i==j:
            continue
        ANS=max(ANS,M[i]+M[j])

for i in T:
    for j in Y:
        ANS=max(ANS,T[i]+Y[j]-A[i][j])

for i in T:
    for j in P:
        # x=i
        # x+y=j

        y=j-i

        if 0<=y<W:
            ANS=max(ANS,T[i]+P[j]-A[i][y])
        else:
            ANS=max(ANS,T[i]+P[j])


for i in T:
    for j in M:
        # x=i
        # x-y=j

        y=i-j

        if 0<=y<W:
            ANS=max(ANS,T[i]+M[j]-A[i][y])
        else:
            ANS=max(ANS,T[i]+M[j])

for i in Y:
    for j in P:
        # y=i
        # x+y=j

        x=j-i

        if 0<=x<H:
            ANS=max(ANS,Y[i]+P[j]-A[x][i])
        else:
            ANS=max(ANS,Y[i]+P[j])


for i in Y:
    for j in M:
        # y=i
        # x-y=j

        x=i+j

        if 0<=x<H:
            ANS=max(ANS,Y[i]+M[j]-A[x][i])
        else:
            ANS=max(ANS,Y[i]+M[j])

for i in P:
    for j in M:
        # x+y=i
        # x-y=j

        x=(i+j)/2
        y=(i-j)/2

        if int(x)==x and int(y)==y and 0<=x<H and 0<=y<W:
            x=int(x)
            y=int(y)
            ANS=max(ANS,P[i]+M[j]-A[x][y])
        else:
            ANS=max(ANS,P[i]+M[j])

print(ANS)