Replace s.next() to s.nextLine() and you will get the desired result.  
- 
next()finds and returns the next complete token from this scanner. A complete token is preceded and followed by input that matches the delimiter pattern. - 
nextLine()returns the rest of the current line, excluding any line separator at the end. The position is set to the beginning of the next line. 
-> "123456 78"
s.next().length() -> "123456".length() -> 6
s.nextLine().length() -> "123456 78".length() -> 9
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solved Java (Length of an input)