var a:array[1..100,1..20] of longint;
      b:array[1..100,1..20] of longint;
      fi, fo:text;
      i, j, m, n:integer;
      s, k, s1:real;
begin
 assign(fi, 'flip.in');
 reset(fi);
 assign(fo, 'flip.out');
 rewrite(fo);
 read(fi, n,m);
  for j:=1 to n do
   for i:=1 to m do
    read(fi, a[i,j]);
     for j:=1 to n do begin
      s:=0; s1:=0; i:=1;
       while i<=m do    begin
                        s:=a[i,j]+s;
                        s1:=-1*s;
                        inc(i);
                        end;
                        if s>=s1 then for i:=1 to m do
                                       b[i,j]:=a[i,j]
                                 else for i:=1 to m do
                                       b[i,j]:=-1*a[i,j];
                      end;
       for i:=1 to m do begin
      s:=0; s1:=0; j:=1;
       while j<=n do    begin
                        s:=b[i,j]+s;
                        s1:=-1*s;
                        inc(j);
                        end;
                        if s>=s1 then for j:=1 to n do
                                       b[i,j]:=b[i,j]
                                 else for j:=1 to n do
                                       b[i,j]:=-1*b[i,j];
                      end;
                      k:=0;
     For j:=1 to n do
      for i:=1 to m do
       k:=b[i,j]+k;
       writeln(fo, k);
       
 close(fi);
 close(fo);
end.