No 555
======

Note: this task is only for students of "Formal languages and
complexity theory" taught in English.

[Your program should read lines from the standard input and check each
 line separately (without end-of-line character). Please use regular
 expressions as much as possible (in particular, try not to use
 logical operators outside the regeular expression). If it is
 possible, use just one regular expression.]

For each string from the standard input, check whether it is a 9-digit
phone number (format "NNN-NNN-NNN" or "NNN NNN NNN"), not beginning
with "555". Write "true"/"false" on the standard output accordingly.

POINTS: 3
DEADLINE: 2019-12-05 17:00