program flip;
var smax,s,ss,sm:longint;
    m,n,i,j,k:byte;
    a:array[1..16,1..16] of longint;
    f,h:text;
begin
assign(f,'flip.in');
assign(h,'flip.out');
reset(f);rewrite(h);
readln(f,n,m);
smax:=0;
for i:=1 to n do
 for j:=1 to m do
  begin
   read(f,a[i,j]);
   smax:=smax+a[i,j];
  end;
for i:=1 to n do
 begin
 s:=0;
 for j:=1 to m do s:=s-a[i,j];
 ss:=0;
 for j:=1 to n do
  for k:=1 to m do ss:=ss+a[j,k];
 if s>0 then begin
               if ss+2*s>smax then
                begin
                 smax:=2*s+ss;
                 for j:=1 to m do a[i,j]:=a[i,j]*(-1);
                end;
              end;
 end;
for i:=1 to m do
 begin
  s:=0;
  for j:=1 to n do s:=s-a[j,i];
  ss:=0;
  for j:=1 to n do
   for k:=1 to m do ss:=ss+a[j,k];
  if s>0 then begin
               if ss+2*s>smax then
                begin
                 smax:=2*s+ss;
                 for j:=1 to n do a[i,j]:=a[i,j]*(-1);
                end;
              end;
 end;
writeln(h,smax);
close(f);close(h);
end.