var n,m,i,j,k,s,smax,q:longint;
    t:array[1..16,1..16]of longint;
    f,g:text;
begin
     assign(f,'flip.in');
     assign(g,'flip.out');
     reset(f); rewrite(g);
     readln(f,n,m);
     for i:=1 to n do for j:=1 to m do read(f,t[i,j]);
     for i:=1 to (1 shl m)-1 do
         begin
              s:=0;
              for k:=1 to n do
                  begin
                       q:=0;
                       for j:=1 to m do
                        if i and (1 shl (j-1))>0 then inc(q,-t[k,j])
                                                 else inc(q,t[k,j]);
                        if q<-q then inc(s,-t)
                                else inc(s,t);
                  end;
              if smax<s then smax:=s;
         end;
     writeln(g,smax);
     close(f);
     close(g);
end.