The second hint will be published on 12th December, 13:00 GMT.
By 5th November, 13:00 GMT, there are 946 participants from 74 countries. 107 solutions to P1 were submitted, out of which 27 were correct:
| First name | Surname | Country | School/University | Date time |
| Yuechen | Zhu | China | Peking University | 21/11/21 13:53 |
| David | Constantinescu | Romania | International Computer High School of Bucharest | 21/11/21 16:58 |
| Alessandro | Rezzi | Italy | University of Padova | 21/11/21 17:59 |
| Luca | Milanese | Italy | Liceo “Leonardo da Vinci”, Terracina | 21/11/21 23:04 |
| Minh Hoàng | Lê | Viet Nam | HUS High School for Gifted Students | 22/11/21 04:31 |
| Zhening Li | Eddie Chen | Canada/United States | Massachusetts Institute of Technology | 22/11/21 06:17 |
| Filip | Vučić | Croatia | I. gymnasium Zagreb | 22/11/21 08:57 |
| Tasuku | Ono | Japan | Harvard University | 22/11/21 17:17 |
| Ameya | Deshmukh | India | IIT Bombay | 23/11/21 07:47 |
| Yeswanth Narayana | Patnana | India | Indian institute of technology Madras | 23/11/21 08:59 |
| Alexandar | Roussev | Bulgaria | First Language School | 23/11/21 11:26 |
| Dženan | Midžić | Bosnia and Herzegovina | JU Gimnazija “Bihać” | 24/11/21 21:51 |
| Matej | Gelev | North Macedonia | Yahja Kemal | 23/11/21 22:18 |
| Sebastián | Arévalo | El Salvador | Instituto Emiliani | 24/11/21 04:08 |
| Vlad-Ștefan | Oros | Romania | “Grigore Moisil” Theoretical High School | 24/11/21 14:10 |
| Isaac | Wu | Australia | University of Melbourne | 25/11/21 05:03 |
| Adam | Džavoronok | Slovakia | Gymnázium Poštová 9 | 25/11/21 17:30 |
| Gabriel | Morais Barros | Brazil | Master | 26/11/21 18:14 |
| Kyle | Bomeisl | United States | Rutgers University | 27/11/21 03:49 |
| Absur Khan | Siam | Bangladesh | Gap Year | 27/11/21 16:46 |
| Cheng Wei | Lin | Taiwan | National Cheng Kung University | 29/11/21 09:05 |
| Jaroslav | Herman | Czech Republic | Charles University | 01/12/21 21:12 |
| Victor | Lequin | France | École Normale Supérieure PSL | 04/12/21 20:10 |
| Ricards | Knipsis | Latvia | University of Manchester | 05/12/21 00:46 |
| Vladimir George | Necula | Romania | International Computer High School of Bucharest | 05/12/21 02:15 |
| Vinícius | Ferreira Rodrigues | Brazil | Universidade de São Paulo | 05/12/21 03:54 |
| Kanishk | Prakhar | India | City Montessori School Gomtinagar Campus-2 | 05/12/21 09:34 |
The list of countries:
Algeria, Argentina, Australia, Azerbaijan, Bangladesh, Belarus, Belgique, Bosnia and Herzegovina, Brazil, Brunei Darussalam, Bulgaria, Canada, China, Costa Rica, Croatia, Czech Republic, Egypt, El Salvador, Estonia, Ethiopia, Finland, France, Georgia, Germany, Greece, Hong Kong, Hungary, India, Indonesia, Iran, Israel, Italy, Japan, Kazakhstan, Korea, Kosovo, Kyrgyzstan, Latvia, Lebanon, Lithuania, Luxembourg, Macao, Malaysia, Mexico, Moldova, Mongolia, Nepal, Nigeria, North Macedonia, Pakistan, Peru, Philippines, Poland, Romania, Russia, Saudi Arabia, Serbia, Singapore, Slovakia, Spain, Sri Lanka, Sweden, Switzerland, Syria, Taiwan, Tajikistan, Thailand, Turkey, Turkmenistan, Ukraine, United Kingdom, United States, Uzbekistan, Vietnam