const d:array[1..2] of integer=(1,-1);
var f,g:text;
    sol:array[0..17] of longint;
    a:array[0..17,0..17] of longint;
    n,m,i,j,suma:longint;
procedure calcul;
 var i,j,s:longint;
 begin
  s:=0;
  for j:=1 to m do begin
   s:=a[1,j];
   for i:=2 to n do
    s:=s+sol[i]*a[i,j];
  end;
  if suma<s then suma:=s;
 end;
procedure back(k:longint);
 var i:longint;
 begin
  if k>n then begin
   calcul;
  end
   else
    for i:=1 to 2 do begin
     sol[k]:=d[i];
     back(k+1);
    end;
 end;
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
  read(f,a[i,j]);
suma:=0;
back(1);
writeln(g,suma);
close(f);
close(g);
end.