const maxn=100;
var a:array[1..maxn] of integer;
    b:array[1..2*maxn] of integer;
    n,i: integer;
    e:boolean;

begin
   readln(n);
   for i:=1 to n do begin
       readln(a[i]);
       b[a[i]]:=a[i];
   end;
   for i:=1 to n do
       if b[i]=0 then begin
          writeln(i);
          e:=true;
          break;
       end;

       if not e then writeln(n+1);
end.