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
for i1 in range(h+2):
  for j1 in range(w+2):
    for i2 in range(h+2):
      for j2 in range(w+2):
        if (1<=i1<=h and 1<=j1<=w) or (1<=i2<=h and 1<=j2<=w):
          continue
        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)