var a:array[1..16,1..16] of longint;
    i,j,n,m,x:byte;
    s,max,ss:longint;
    f,g:text;
    b:array[0..16] of byte;
begin
assign(f,'flip.in');reset(f);
assign(g,'flip.out');rewrite(g);
readln(f,n,m);
for i:=1 to n do begin
 for j:=1 to m do
   read(f,a[i,j]);
   readln(f);
end;
x:=1;
for i:=1 to n do
 b[i]:=0;
 while x>0 do begin
    if b[x]<2 then b[x]:=b[x]+1;
    if x=n then begin
     ss:=0;
for j:=1 to m do begin
   s:=0;
  for i:=1 to n do begin
   if b[i]=2 then
    s:=s-a[i,j] else
    s:=s+a[i,j];
    end;
       if s<0 then ss:=ss-s
       else ss:=ss+s;
  end;
  if ss>max then max:=ss;
      while b[x]=2 do begin
       x:=x-1;
        end;
    end else begin
    x:=x+1;
    b[x]:=0;
    end
    end;
  writeln(g,max);
close(f);
close(g);
end.