Congratulations to Ján Buša! On June 30, 2023, Ján Buša, Deputy Director for Scientific Work of the Meshcheryakov Laboratory of Information Technologies (MLIT) of the Joint Institute for Nuclear Research (JINR), Candidate of Physical and Mathematical Sciences, Associate Professor, celebrates his 65th birthday. Ján Buša was born in Košice, Czechoslovakia. During 1977-1982, Ján studied at the Faculty of Computational Mathematics and Cybernetics of Lomonosov Moscow State University (FCMC-MSU), where he graduated with honors. He immediately continued the doctoral studies at the FCMC-MSU, defending in 1987 his PhD thesis "Study of equations with input inaccurate information", under the guidance of Academician A.N. Tikhonov. From December 1986 to May 2019, J. Buša teached applied mathematics at the Department of Mathematics of the Faculty of Electrical Engineering of the Technical University of Košice, Slovakia. In 2017, he became an associate professor in computer science (“Algorithms and software implementation for solving selected problems of computational geometry”). Ján Buša is the author and co–author of about 50 journal scientific papers and 30 reports at International conferences, as well as several monographs and dozens of training courses. He translated into Slovak a remarkable book by A. N. Tikhonov, A.V. Goncharsky, V. V. Stepanov, A. G. Yagola "Numerical methods for solving ill-posed problems" (Moscow: Nauka, 2000, 268 p.). J. Buša's cooperation with JINR started in 1995, when he came to the first (out of twelve) three-month business trip to LCTA (LIT). Ján took an active part in the development of the scientific cooperation between Slovak and JINR scientists. For many years he was a member of the Committee of the Plenipotentiary Representative of Slovakia to JINR. Since 2006, he has been a member of the organizing or program committees of seven International MMCP ("Mathematical Modeling and Computational Physics") Conferences organized by LIT JINR and other institutions in Slovakia and Dubna. He was also the scientific secretary of the MMCP Conferences held in Slovakia. He joined the group of editors of the Proceedings of the MMCP 2011 Conference, published in “Lecture Notes in Computer Science”, and MMCP 2015, 2017 and 2019, published in “EPJ - Web of Conferences”. In September 2018, J. Buša was elected to the position of LIT Deputy Director for Scientific Work As co-leader of the scientific topic 05-6-1119-2014/2023 "Methods, algorithms and software for modeling physical systems, mathematical processing and analysis of experimental data", he did a great deal of organizational work. Ján enjoys well-deserved authority and respect among colleagues who highly appreciate his managing and human qualities – erudition, scientific integrity, goodwill and caring attitude to others. Ján Buša was awarded the Prize of the Minister of Education of the Slovak Republic (1982) and the Gold Medal of Prof. Janský for blood donation. Together with his wife Tatiana, they raised a son and two daughters, they are happy with their grandson and seven granddaughters. Dear Ján! We heartfully congratulate you on your anniversary. We wish you good health, energy and success in your work, well-being, mutual understanding and happiness in family life! All the very best to you! The JINR Directorate, the Directorate of the Meshcheryakov Laboratory of Information Technologies, colleagues and friends .