import sys
input = sys.stdin.readline
h,w = map(int,input().split())
grid = []
for i in range(h):
    grid.append(list(map(int,input().split())))

ans = 0
dxy = [[[1,-1],[1,0],[1,1]],[[-1,-1],[-1,0],[-1,1]],[[-1,1],[0,1],[1,1]],[[-1,-1],[0,-1],[1,-1]]]

s = set()

for j in range(w+2):
    s.add((0,j,0))
    s.add((h,j,1))


for j in range(h+2):
    s.add((j,0,2))
    s.add((j,w,3))

for x,y,e in s:
    for dx,dy in dxy[e]:
        temp = 1
        cnt = 0
        se = set()
        while 1 <= x+dx*temp <= h and 1 <= y+dy*temp <= w:
            cnt += grid[x+dx*temp-1][y+dy*temp-1]
            se.add((x+dx*temp-1,y+dy*temp-1))
            temp += 1
        if temp == 1:
            continue
        
        for u,v,o in s:
            if x == u and y == v:
                continue
            for dx,dy in dxy[o]:
                c = 0
                temp = 1
                while 1 <= u+dx*temp <= h and 1 <= v+dy*temp <= w:
                    if (u+dx*temp-1,v+dy*temp-1) in se:
                        temp += 1
                        continue
                    c += grid[u+dx*temp-1][v+dy*temp-1]
                    temp += 1
                ans = max(ans,cnt+c)
print(ans)