program flip;
type matrice=array[1..17,1..17]of longint;
var a:matrice;f,g:text;i,x,j,m,n:integer;ss,s,maxim:longint;
    v:array[0..17] of integer;
begin
assign(f,'flip.in');reset(f);
assign(g,'flip.out');rewrite(g);
readln(f,n,m);
maxim:=0;
for i:=1 to n  do
 for j:=1 to m do
 begin
  read(f,a[i,j]);
  maxim:=maxim+a[i,j];
 end;
{ readln(f);}
while (v[0]=0) do
begin
 j:=m;
 while v[j]=1 do
  begin
   v[j]:=0;
   j:=j-1;
  end;
 v[j]:=1;
 s:=0;
 for i:=1 to n do
 begin
 ss:=0;
 for x:=1 to m do
   if v[x]=1 then
    ss:=ss-a[i,x]
    else
    ss:=ss+a[i,x];
  if ss<0 then ss:=ss*(-1);
  s:=s+ss;
  end;
 if s>maxim then maxim:=s;
end;
 writeln(g,maxim);
close(f);
close(g);
end.