var b:array[1..16,1..16]of longint;
    a:array[1..32]of shortint;
    n,m:byte; max:longint; f:text;

procedure citire;
var i,j:byte; f:text;
begin
 assign(f,'flip.in');
 reset(f);
 readln(f,n,m);
 for i:=1 to n do
  begin
   for j:=1 to m do read(f,b[i,j]);
   readln(f);
  end;
 close(f);
end;



function calcul:longint;
var i,j:byte;k:longint;
begin
 k:=0;
 for i:=1 to n do
  for j:=1 to m do k:=k+b[i,j]*a[i]*a[n+j];
 calcul:=k;
end;


procedure gen_bin(p:byte);
var k:longint;
begin
 if p>n+m then
  begin
   k:=calcul;
   if k>max then max:=k;
  end else begin
   a[p]:=-1; gen_bin(p+1);
   a[p]:=1; gen_bin(p+1);
  end;
end;

begin
 max:=0;
 citire;
 gen_bin(1);
 assign(f,'flip.out');
 rewrite(f);
 writeln(f,max);
 close(f);
end.