2n.1n.py

str = 'akugantengkalopasgelap'

for i in range(0, len(str), 2):
    p1 = str[:i]
    s1 = '.'.join(p1[x:x + 2] for x in range(0, len(p1), 2))
    s2 = '.'.join(str[i:])
    print(f'{s1}.{s2}'.lstrip('.'))