Program Flip;
type max = 1..16;
tab = array[max,max] of -1000000..1000000;
var n,m,i,j:max;
fl:tab;
semn: array[max] of 0..1;
a,maxim:longint;
f,g:text;
function Solutie:longint;
var i,j:max;
sum,s:longint;
begin
 for i:=1 to n do begin
  s:=0;
  for j:=1 to m do
   if semn[j] = 0 then
    s:=s+fl[i,j]
    else
    s:=s-fl[i,j];
  if s>0 then
  sum:= sum+s
  else
  sum:= sum-s;
 end;
 Solutie:=s;
end;
procedure backtrack(var maxim:longint;k:max);
var x: longint;
begin
 if k > m then begin
  x:= solutie;
  if x > maxim then maxim:= x;
  exit;
  end;
semn[k]:=0;
backtrack(k+1);
semn[k]:=1;
backtrack(k+1);
end;
begin
assign(f,'flip.in');assign(g,'flip.out');
reset(f);rewrite(g);
readln(f,n,m);
for i:=1 to n do begin
for j:=1 to m do
 read(f,fl[i,j]);
readln(f);
end;
Backtrack(1);
writeln(g,maxim);
close(f);close(g);
end.