var f,g:text;
    a:array[1..17,1..17] of longint;
    x:array[0..17] of integer;
    i,n,m,j,s,max,ss:longint;
begin
     assign(f,'flip.in');reset(f);
     assign(g,'flip.out');rewrite(g);
     read(f,n,m);
     for i:=1 to n do
         for j:=1 to m do
             begin
             read(f,a[i,j]);
             max:=max+a[i,j];
             end;
     while x[0]=0 do
           begin
                i:=n;
                while x[i]=1 do begin x[i]:=0;i:=i-1; end;
                x[i]:=1;
                s:=0;
                for j:=1 to m do
                    begin
                         ss:=0;
                         for i:=1 to n do
                             if x[i]=1 then ss:=ss-a[i,j]
                                       else ss:=ss+a[i,j];
                         //if ss<0 then ss:=-ss;
                         s:=s+ss;
                    end;
                if max<s then max:=s;
           end;
     writeln(g,max);
close(f);
close(g);
end.