var a:array[1..17,0..17] of longint;
    f:text;
    lin,col,i,j,n,m:integer;
    x,ct,summ,summax,sumlin:longint;

begin
  assign(f,'flip.in');
  reset(f);
  read(f,n,m);
  for i:=1 to n do
    for j:=0 to m-1 do begin
      read(f,x);
      if n<m then
        a[j,i]:=x
      else
        a[i,j]:=x;
    end;
  close(f);
  if n<m then begin
    x:=n;
    n:=m;
    m:=x;
  end;
  summax:=-2000000;
  for ct:=0 to 1 shl m -1 do begin
    summ:=0;
    for lin:=1 to n do begin
      sumlin:=0;
      for col:=0 to m-1 do
        if (ct shr col) and 1 = 0 then sumlin:=sumlin+a[lin,col]
                                else sumlin:=sumlin-a[lin,col];
      if sumlin>0 then summ:=summ+sumlin
      else summ:=summ-sumlin;
    end;
    if summ>summax then summax:=summ;
  end;

  assign(f,'flip.out');
  rewrite(f);
  write(f,summax);
  close(f);
end.