ðˈɛɹfoːɹ, ɪf nˈʌmbɚ sˈɛvən sˈɛz nˈʌmbɚ θˈɜːtiːn ðˈɛn nˈʌmbɚ θˈɜːtiːn kænˈɑːt sˈeɪ nˈʌmbɚ sˈɛvən, ænd lˈaɪkwaɪz hˌuː ˈɛvɚ nˈʌmbɚ θˈɜːtiːn sˈɛz, kænˈɑːt sˈeɪ nˈʌmbɚ θˈɜːtiːn bˌʌt ðeɪ kʊd sˈeɪ nˈʌmbɚ sˈɛvən.
Therefore, if number 7 says number 13 then number 13 cannot say number 7, and likewise who ever number 13 says, cannot say number 13 but they could say number 7.