Hong Kong secondary and primary school student readers are welcome to submit solutions (with proofs) via email to email@example.com, specifying the student’s name in Chinese and in English, the school’s name in Chinese and in English, and the student’s class in the email. Each student may send at most one email. Souvenirs will be awarded to the first 20 students solving the most questions on the condition that each school can have at most 3 awardees. Solutions can be submitted in Chinese or English. Both typed and scanned files are acceptable. The awardees will be announced in the next issue. The decision of the Organising Committee of the 57th International Mathematical Olympiad on any matter of this activity is final. Enquiries may be emailed to firstname.lastname@example.org.