Proposed by Daniel Sitaru-Romania
Solution 1 by Yen Tung Chung-Taichung-Taiwan, Solution 2 by Hussain Reza Zadah-Afghanistan, Solution 3 by Ravi Prakash-New Delhi-India, Solution 4 by Orlando Irahola Ortega-Bolivia, Solution 5 by Abner Chinga Bazo-Peru
