h,w=map(int,input().split())
a=[[0]*(w+2)]
for i in range(h):
  a+=[[0]+list(map(int,input().split()))+[0]]
a+=[[0]*(w+2)]
v=[[0]*(w+2) for i in range(h+2)]
g=0
c=0
s=[]
for i in range(h+2):
  for j in range(w+2):
    if 1<=i<=h and 1<=j<=w:
      continue
    s+=[(i,j)]
for i1,j1 in s:
  for i2,j2 in s:
    for dx1 in [-1,0,1]:
      for dy1 in [-1,0,1]:
        for dx2 in [-1,0,1]:
          for dy2 in [-1,0,1]:
            if (dx1,dy1)==(0,0) or (dx2,dy2)==(0,0):
              continue
            c+=1
            p=0
            x1=i1
            y1=j1
            while 0<=x1+dx1<=h+1 and 0<=y1+dy1<=w+1:
              x1+=dx1
              y1+=dy1
              if v[x1][y1]!=c:
                v[x1][y1]=c
                p+=a[x1][y1]
            x2=i2
            y2=j2
            while 0<=x2+dx2<=h+1 and 0<=y2+dy2<=w+1:
              x2+=dx2
              y2+=dy2
              if v[x2][y2]!=c:
                v[x2][y2]=c
                p+=a[x2][y2]
            g=max(g,p)
print(g)