PROGRAMMING:2017final English sentence format simple check

In English writing, the first letter of a sentence is usually uppercase, and the rest is lowercase, except for the word "I". Words are separated by a space, and "," is used in the sentence to break the sentence, and "." is used at the end of the sentence. There is no need to separate "," and "." from their preceding words. Word and other text editors usually automatically correct the English sentences we input according to the above rules. Please write a function to input an English sentence in the correct format according to the above rules. For example, for the input English sentence "this is an example with one mistake." because the character "e" in the word "example" should be lowercase "e", the correct format of the output sentence is this is an example with one mistake
be careful:
1、 Each group of test data includes only one English sentence ending with the character ".".
2、 The characters in the input English sentences include 26 upper case English letters (ASCII code 65-90), 26 lower case English letters (ASCII code 97-122), "," and "." and space characters.
###Input format:
An English sentence ending with the character ".".
###Output format:
Input English sentences and output them after format correction.
###Input example:
```in
This is an Example with one mistake.
```
###Output example:
```out
This is an example with one mistake.
```






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