The Messenger of Allah said to me: 'When you perform ablution, clean your nose, and when you use pebbles to clean yourself after defecating, use an odd number.'" (Using translation from Ibn Mājah 406)
"إذَا توضَّأتَ فانْتثِرْ، وإذا استجْمَرْتَ فأوْتِرْ".