var n,m,i,j:longint;
    a:array[1..16,1..16]of longint;
    l,c:array[1..16]of shortint;
    bufin:array[1..65000]of byte;
    s:int64;

begin
  assign(input,'flip.in'); reset(input);
  assign(output,'flip.out'); rewrite(output);
  settextbuf(input,bufin);

  readln(n,m);
  for i := 1 to n do
  begin
    for j := 1 to m do
      read(a[i,j]);
    readln();
  end;

  for j := 1 to m do
  begin
    s := 0;
    for i := 1 to n do
      s := s + a[i,j];
    if s >= 0 then c[j] := 1 else c[j] := -1;
  end;
  for i := 1 to n do
  begin
    s := 0;
    for j := 1 to m do
      s := s + a[i,j]*c[j];
    if s >= 0 then l[i] := 1 else l[i] := -1;
  end;

  s := 0;
  for i := 1 to n do
    for j := 1 to m do
    begin
      s := s + a[i,j] * l[i]*c[j];
    end;

  writeln(s);

  close(input);
  close(output);
end.