from copy import deepcopy
deg=[(0,1),(1,0),(1,1),(-1,1)]
H,W=map(int,input().split())
A=[list(map(int,input().split())) for i in range(H)]
beam=[]
for i in range(W+1):
    for xd,yd in deg:
        x=i
        y=0
        x+=xd
        y+=yd
        now=0
        while 1<=x<=W and 1<=y<=H:
            now+=A[y-1][x-1]
            x+=xd
            y+=yd
        if now!=0:
            beam.append((now,i,0,xd,yd))
for i in range(H+1):
    for xd,yd in deg:
        x=0
        y=i
        x+=xd
        y+=yd
        now=0
        while 1<=x<=W and 1<=y<=H:
            now+=A[y-1][x-1]
            x+=xd
            y+=yd
        if now!=0:
            beam.append((now,0,i,xd,yd))
ap=deepcopy(A)
beam.sort(reverse=True)
ans1=0
for p in range(min(len(beam),100)):
    A=deepcopy(ap)
    x=beam[p][1]
    y=beam[p][2]
    xd=beam[p][3]
    yd=beam[p][4]
    x+=xd
    y+=yd
    ans=beam[p][0]
    while 1<=x<=W and 1<=y<=H:
        A[y-1][x-1]=0
        x+=xd
        y+=yd
    maxi=0
    for i in range(W+1):
        for xd,yd in deg:
            x=i
            y=0
            x+=xd
            y+=yd
            now=0
            while 1<=x<=W and 1<=y<=H:
                now+=A[y-1][x-1]
                x+=xd
                y+=yd
            maxi=max(maxi,now)
    for i in range(H+1):
        for xd,yd in deg:
            x=0
            y=i
            x+=xd
            y+=yd
            now=0
            while 1<=x<=W and 1<=y<=H:
                now+=A[y-1][x-1]
                x+=xd
                y+=yd
            maxi=max(maxi,now)
    ans1=max(ans1,ans+maxi)
print(ans1)