H,W=map(int,input().split())
A=[]
A.append([0]*(H+2))
for i in range(H):
    A.append([0]+list(map(int,input().split()))+[0])
A.append([0]*(H+2))
starts=[]
for i in range(H+1):
    for j in range(W+1):
        for dx in range(-1,2):
            for dy in range(-1,2):
                if i==H+1 or i==0 or j==0 or j==W+1:
                    if 1<=i+dx<=H and  1<=j+dy<=W:
                        starts.append([i,j,dx,dy])
pos_to_ans={}
for i,j,dx,dy in starts:
    ans=0
    i2,j2=i,j
    while 1<=i2+dx<=H and 1<=j2+dy<=W:
        i2+=dx
        j2+=dy
        ans+=A[i2][j2]
    pos_to_ans[(i,j,dx,dy)]=ans
dic={}
Set=set()
for i in range(1,H):
    for j in range(1,W):
        last=[]
        for dx in range(-1,2):
            for dy in range(-1,2):
                if dx==dy==0:
                    continue
                i2,j2=i,j
                while 1<=i2<=H and 1<=j2<=W:
                    i2+=dx
                    j2+=dy
                last.append((i2,j2,dx,dy))
        for x1,y1,dx1,dy1 in last:
            for x2,y2,dx2,dy2 in last:
                dic[(x1,y1,dx1,dy1,x2,y2,dx2,dy2)]=A[i][j]
print(dic)
ans=0
for i,j,dx,dy in starts:
    for i2,j2,dx2,dy2 in starts:
        ans_d=pos_to_ans[(i,j,dx,dy)]+pos_to_ans[(i2,j2,dx2,dy2)]
        ge=dic.get((i,j,dx,dy,i2,j2,dx2,dy2))
        if ge!=None:
            ans_d-=ge
        ans=max(ans,ans_d)
print(ans)