program Flip;
var
   Fl : text;
   a : array[1..16,1..16] of longint;
   b : array[1..33] of longint;
   n, m, i, j : shortint;
   s, k : longint;

procedure Comutator_linii(in1: shortint);
var
   i, j: shortint;
begin
   for j := 1 to m do
      a[in1,j] := a[in1,j] * -1;
end;
procedure Comutator_coloane(in1 : shortint);
var
   i : shortint;
begin
   for i := 1 to n do
      a[i,in1] := a[i,in1] * -1;
end;
begin
   Assign(Fl,'flip.in');
   Reset(Fl);
   ReadLn(Fl,n,m);
   for i := 1 to n do
      for j := 1 to m do
         Read(Fl,a[i,j]);
   Close(Fl);

   for i := 1 to n do
      begin
         s := 0;
         for j := 1 to m do
            s := s + a[i,j];
         if s < 0 then
            Comutator_linii(i);
      end;

   for i := 1 to m do
      begin
         s := 0;
         for j := 1 to n do
            s := s + a[j,i];
         if s < 0 then
            Comutator_coloane(i);
      end;

   s := 0;
   for i := 1 to n do
      for j := 1 to m do
         s := s + a[i,j];

   Assign(Fl,'flip.out');
   ReWrite(Fl);
   WriteLn(Fl,s);
   Close(Fl);
end.