Answer:
hfufbrdubedyg gxnsbetxyfbrdybeuxuabrbxybsbcyebdydbehdhdhdhcubdenudnejwjw7xtrwhajaobcbdggevejaveyxbwbgzfybaegnesujwbghene8hav ejuzvwbfhuh bsndndbchchychdbruxnejxne7hdrhxhehnxurnxhhbehdndjndhd
21%4 is 1.
21-4=17
17-4=13
13-4=9
9-4=5
5-4=1
I believe it’s a default application.