const t=1000003;

var f,g:Text;
    a:array[0..100000]of shortint;
    n,m,i,x:longint;
    c:int64;

begin
assign(f,'grigo.in');
assign(g,'grigo.out');
reset(f);
rewrite(g);
read(f,n,m);
for i:=1 to m do
  begin
    read(f,x);
    a[x]:=1;
  end;
c:=1;
for i:=2 to n do
  begin
    if (a[i]=0)then
      c:=(c*(i-1))mod t;
  end;
write(g,c);
close(f);
close(g);
end.