import sys
input = sys.stdin.readline
def read_values(): return tuple(map(int, input().split()))
def read_list(): return list(read_values())

def main():
    h,w=read_values()
    a=[]
    for _ in range(h):
        a.append(read_list())
    ans=0
    sumH=[0]*(h+w)
    sumW=[0]*(h+w)
    sumHpW=[0]*(h+w)
    sumHmW=[0]*(h+w)
    for i in range(h):
        for j in range(w):
            sumH[i]+=a[i][j]
            sumW[j]+=a[i][j]
            sumHpW[i+j]+=a[i][j]
            sumHmW[i-j+w]+=a[i][j]
    
    s=set()
    for i in range(h):
        for j in range(w):
            ans=max(ans,sumH[i]+sumW[j]-a[i][j])
            ans=max(ans,sumH[i]+sumHpW[i+j]-a[i][j])
            ans=max(ans,sumH[i]+sumHmW[i-j+w]-a[i][j])
            ans=max(ans,sumW[j]+sumHpW[i+j]-a[i][j])
            ans=max(ans,sumW[j]+sumHmW[i-j+w]-a[i][j])
            ans=max(ans,sumHpW[i+j]+sumHmW[i-j+w]-a[i][j])
            s.add((0,i,1,j))
            s.add((0,i,2,i+j))
            s.add((0,i,3,i-j+w))
            s.add((1,j,2,i+j))
            s.add((1,j,3,i-j+w))
            s.add((2,i+j,3,i-j+w))
                    
    for v in range(4):
        for i in range(h+w):
            for j in range(i+1,h+w):
                a1=[sumH[i],sumW[i],sumHpW[i],sumHmW[i]][v]
                a2=[sumH[j],sumW[j],sumHpW[j],sumHmW[j]][v]
                ans=max(ans,a1+a2)                
            for v2 in range(v+1,4):
                for j in range(h+w):
                    if (v,i,v2,j) in s:
                        continue
                    a1=[sumH[i],sumW[i],sumHpW[i],sumHmW[i]][v]
                    a2=[sumH[j],sumW[j],sumHpW[j],sumHmW[j]][v2]
                    ans=max(ans,a1+a2)
    print(ans)

if __name__ == "__main__":
    main()