var l,k,i,j,m,n,max:longint;
    c,b,a:array[1..16,1..16] of longint;
    f,g:text;
procedure load;
begin
assign(f,'flip.in');
reset(f);
readln(f,n,m);
for i:=1 to n do
begin
for j:=1 to m do
begin
read(f,a[i,j]);
b[i,j]:=a[i,j];
end;
readln(f);
end;
close(f);
assign(g,'flip.out');
rewrite(g);
end;
function suma:longint;
var i,j:integer;
    s:longint;
begin
s:=0;
for i:=1 to n do
for j:=1 to m do
s:=s+a[i,j];
suma:=s;
end;
procedure init_a;
var i,j:integer;
begin
for i:=1 to n do
for j:=1 to m do
a[i,j]:=b[i,j];
end;
procedure retconf_a;
var i,j:integer;
begin
for i:=1 to n do
 for j:=1 to m do
  c[i,j]:=a[i,j];
end;
procedure daval_a;
var i,j:integer;
begin
for i:=1 to n do
 for j:=1 to m do
  a[i,j]:=c[i,j];
end;
BEGIN
load;
max:=-maxlongint;
for i:=1 to n do
begin
init_a;
for j:=1 to m do
a[i,j]:=-a[i,j];
retconf_a;
for k:=1 to m do
begin
daval_a;
for l:=1 to n do
a[k,l]:=-a[k,l];
if suma>max then max:=suma;
end;
end;
writeln(g,max);
close(g);
END.