type matrix=array[1..16,1..16] of longint;tomb=array[1..2,1..16] of integer;
var i,j,k,m,n,l,h:integer;van,jo:boolean;t:matrix;v:tomb;f,g:text;s,max:longint;
procedure kovetkezo(k:integer;var van:boolean);
begin
        van:=false;
        if k=n then
                l:=2;
        if (v[l,k]<1) and (k<m) and (k<n) then
        begin
                van:=true;
                v[l,k]:=v[l,k]+1;
        end;
end;
procedure ellenoriz(var jo:boolean);
begin
        s:=0;
        for i:=1 to m do
                for j:=1 to n do
                        begin
                                s:=s+t[i,j];
                                if v[1,i]=1 then
                                        s:=s-2*t[i,j]
                                else
                                        if v[2,j]=1 then
                                                s:=s-2*t[i,j];
                        end;
        if s>max then
        begin
                jo:= true;
                max:=s;
        end;
end;
BEGIN
        assign(f,'flip.in');assign(g,'flip.out');
        reset(f);read(f,m,n);k:=1;l:=1;v[l,k]:=-1;
        for i:=1 to m do
                for j:=1 to n do
                        read(f,t[i,j]);
        close(f);
        while k>0 do
        begin
                repeat
                        kovetkezo(k,van);
                        if van then
                                ellenoriz(jo);
                until ((van) and (jo)) or (not van);
                if not van then
                        k:=k-1
                else
                begin
                        k:=k+1;
                        v[l,k]:=-1;
                end;
        end;
        rewrite(g);write(g,max);close(g);
end.