PROGRAMMING:Judge whether the e-mail address is legal

Enter a string to judge whether it is a legal mailbox (the format is correct, no matter whether it really exists or not). The input can only be letters, numbers, underscores, @ and. The front and back of @ can only be letters or numbers, and the back of. Can only be com. If yes, output yes, otherwise output No.
###Input format:
A string of characters.
###Output format:
For each input, output yes or no.
###Input example:
```in
adf12@qw213.com
```
###Output example:
```out
YES
```







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