PROGRAMMING:Longest symmetric substring

For a given string, this problem requires you to output the length of the longest symmetric substring. For example, given 'is Pat & Tap symmetry?', The longest symmetric substring is's pat & Tap s', so you should output 11.
###Input format:
Enter a non empty string with a length of no more than 1000 in one line.
###Output format:
Outputs the length of the longest symmetric substring in a row.
###Input example:
```in
Is PAT&TAP symmetric?
```
###Output example:
```out
eleven
```






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