var 
	f:text;
	x,y,i,j,max,sum,a,b:integer;
	t,t2:array[1..16,1..16] of longint;
	
begin
	assign(f,'flip.in');
	reset(f);
	readln(f,y,x);
	for j:=1 to y do begin
		for i:=1 to x-1 do
			read(f,t[i,j]);
		readln(f,t[x,j]);
	end;
	close(f);
	
	for j:=1 to y do 
		for i:=1 to x do max:=max+t[i,j];
	for b:=1 to y do 
		for a:=1 to x do begin
			sum:=0;
			for j:=1 to y do 
				for i:=1 to x do
					t2[i,j]:=t[i,j];
			for j:=1 to y do 
				for i:=1 to x do begin
					if j=b then t2[i,j]:=t2[i,j]*-1;
					if i=a then t2[i,j]:=t2[i,j]*-1;
				end;
			for j:=1 to y do 
				for i:=1 to x do
					sum:=sum+t2[i,j];
			if max<sum then max:=sum;
		end;
	
	assign(f,'flip.out');
	rewrite(f);
	writeln(f,max);
	close(f);
end.