In problem B of today's round (987), same solution submitted with PyPy 3.6 TLEd while it worked in PyPy3.10 and Python 3.8. What could be the possible reason?

PyPy 3.6 : https://mirror.codeforces.com/contest/2031/submission/291663544
PyPy 3.10 : https://mirror.codeforces.com/contest/2031/submission/291664045
Python 3.8 : https://mirror.codeforces.com/contest/2031/submission/291664084