# [Python 2], <s>108</s> 97 bytes

<!-- language-all: lang-python -->

    i=input().split(".")
    for x in range(len(i)-(1,2)[ord(i[-1][0])<91]):i[x]=i[x][0]
    print".".join(i)

[Try it online!]

[Python 2]: https://docs.python.org/2/
[Try it online!]: https://tio.run/nexus/python2#FYwxDgIhEAD7ewWhWhJvI3Yar7ov2BEKciJZRZYAJvd75JopJpnptFDKvwYKa47UQKJU04uL2AUlUVwKHqJPQGoGfboow@UJZGZtzdmq@1VbdSOz2@XAUFMulNq44JvpyHqXG38xMIfoMfIYFsxu@7jg8eFrW6OrVf4B "Python 2 – TIO Nexus"