var a,b,c:array[1..16,1..16] of longint;
        n,m,i,j,smax:longint;
        st:array[1..16] of -1..1;
        f,g:text;
   procedure verif(k:integer);
    var i,j,ss,s:longint;
   begin
         for i:=1 to k do
              if st[i]=-1 then c[i]:=b[i]
                         else c[i]:=a[i];
        ss:=0;
        for j:=1 to m do
        begin
             s:=0;
             for i:=1 to n do s:=s+c[i,j];
             if s<0 then ss:=ss-s
                    else ss:=ss+s;
        end;
        if ss>smax then smax:=ss;
   end;
   procedure gen(k:integer);
   begin
        if k=n+1 then verif(k-1)
                 else
                  begin
                       st[k]:=-1;
                      gen(k+1);
                       st[k]:=1;
                       gen(k+1);
                  end;
   end;
   begin
        assign(f,'flip.in'); reset(f);
        assign(g,'flip.out'); rewrite(g);
        readln(f,n,m);
        for i:=1 to n do
             for j:=1 to m do
             begin
                 read(f,a[i,j]);
                 b[i,j]:=-a[i,j];
            end;
        smax:=-maxlongint;
        gen(1);
        writeln(g,smax);
       close(g);
 end.