Python

can anyone help me find the cause of the loop plz m=0 from itertools import product ss=[] for t in product ('012', repeat=49) : t=str(''.join(t)) if t.count('0') ==19 and t.count('1') ==13: ss.append(t) for s in ss: while '10' in s or '20' in s: if '20' in s: s=s.replace('20', '00', 1) else: s=s.replace('10', '200', 1) if s.count ('0') >m: m=s.count('0') print(m)