a.py

import re

string = input().rstrip().lstrip()

string = string.lower()
string = re.sub("\.{1}\s*", ". ", string)
tmp_string = string
string = string.split(". ")
string = list(filter(lambda x: len(x), string))

if len(string) != tmp_string.count('.'):
    print(-1)
else:
    string = list(map(lambda x: x.split(" "), string))

    for i in range(len(string)):
        for k in range(len(string[i])):
            string[i][k] = string[i][k]

            if k == 0:
                string[i][0] = string[i][0][0].upper() + string[i][0][1:]

    string = list(map(lambda x: list(filter(lambda y: len(y), x)), string))
    tmp = ""
    for sentence in string:
        for word_id in range(len(sentence)):
            if word_id != len(sentence) - 1:
                tmp += sentence[word_id].replace(" ", "") + ' '
        tmp += sentence[-1].replace(" ", "")
        tmp += ". "

    tmp = re.sub("(\s)+", " ", tmp)

    if re.match("(\s{0}([A-Z]{1}[a-z]{0,}){1}(\s[a-z]{1,}){0,}\.{1}){1,}(\s{1}([A-Z]{1}[a-z]{0,}){1}(\s[a-z]{1,}){0,}\.{1}){0,}", tmp):
        print(tmp)
    else:
        print(-1)