program flip;
type matrice = array [1..17,1..17] of longint;
var x:matrice;
    i,j:integer;
    mm,max,ma,n,m:longint;
    fin,fout:text;
begin
  assign(fin,'flip.in');
  assign(fout,'flip.out');
  reset(fin);
  rewrite(fout);
  readln(fin,n,m);
  for i:=1 to n do
    begin
      for j:=1 to m do
        read(fin,x[i,j]);
      readln(fin);
    end;

  for i:=1 to m do
    begin
      ma:=0;
      mm:=0;
      for j:=1 to n do
        begin
          ma:=ma+x[j,i];
          mm:=mm+x[j,i]*-1;
        end;
      if mm > ma then
        begin
          for j:=1 to n do
            begin
              x[j,i]:=x[j,i]*-1;
            end;
        end;
    end;
  max:=0;
  for i:=1 to n do
    begin
      ma:=0;
      mm:=0;
      for j:=1 to m do
        begin
          ma:=ma+x[i,j];
          mm:=mm+x[i,j]*-1;
        end;
      if mm > ma then
        begin
          for j:=1 to m do
            begin
              x[i,j]:=x[i,j]*-1;
            end;
        end;
    end;
  for i:=1 to m do
    begin
      ma:=0;
      mm:=0;
      for j:=1 to n do
        begin
          ma:=ma+x[j,i];
          mm:=mm+x[j,i]*-1;
        end;
      if mm > ma then
        begin
          for j:=1 to n do
            begin
              x[j,i]:=x[j,i]*-1;
            end;
        end;
    end;
  for i:=1 to n do
    begin
      for j:=1 to m do
        max:=max+x[i,j];
    end;
  writeln(fout,max);
  close(fout);
end.