You could say 'two', and then argue your point.
There is a summary of the yes/no responses if you go to https://forum.duolingo.com/topic/924/hot and see the sticky discussion 'Saying yes and no in Welsh'.
- If a question does not start with a verb, use Ie/Nage for Yes/No. (There are some local variations such as Ia/Naci, etc)
- Otherwise, if a question is in the simple past tense, use Do/Naddo. (Some dialects use that in some other tenses, too.)
- Otherwise, various verb forms are used ...
In casual speech and slang, things often get simplified.