program grigo;
    var a:Array[0..100000] of boolean; f,g:text;   nr,i,n,m,max:longint;   rez: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;  
       rez:=1;  
       for i:=1 to n-1 do   if a[i]=false then   rez:=(rez*i) mod 1000003;  
       writeln(g,rez);  
    close(f); close(g);  
   end.