"The Messenger of Allah said: 'Whoever performs ablution, let him clean his nose, and whoever uses pebbles to clean himself after defecating, let him use an odd number.'" (Using translation from Ibn Mājah 409)
أَنَّ رَسُولَ اللهِ ﷺ قَالَ مَنْ تَوَضَّأَ فَلْيَسْتَنْثِرْ وَمَنْ اسْتَنْجَى فَلْيُوتِرْ