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.