var
	a:array[1..16,1..16] of longint;
	n,m,i,j,k:longint;
	suma,fin,s,ps:longint;
	
begin
	assign(input,'flip.in');reset(input);
	assign(output,'flip.out');rewrite(output);
	readln(n,m);
	fillchar(a,sizeof(a),0);
	for i:=1 to n do
		for j:=1 to m do
			read(a[i][j]);
	fin:= 1 shl m;
	suma:=0;
	for k:=1 to fin do begin
		s:=0;
		for i:=1 to n do begin
			ps:=0;
			for j:=1 to m do begin
				if k and (1 shl j) > 0 then ps:=ps-a[i][j] else ps:=ps+a[i][j];
			end;
			if ps < 0 then s:=s-ps else s:=s+ps;
		end;
		if s > suma then suma:=s;
	end;
	writeln(suma);
end.