var a:array[0..100000] of boolean;
    f,g:text;
    i,n,m,max:longint;
    r:int64;
    ok:boolean;
begin
assign(f,'grigo.in');
reset(f);
assign(g,'grigo.out');
rewrite(g);
read(f,n,m);
for i:=1 to m do begin
                 read(f,max);
                 a[max-1]:=true;
                 end;
r:=1;
for i:=1 to n-1 do if a[i]=false then r:=(r*i) mod 1000003;
writeln(g,r);
close(f);
close(g);
end.