Relation means Table. Three tables will be formed: two for entities and one for M:N relationship.
1NF requires attributes to be atomic.
Relation is a set of tuples and that's why it can't have duplicate tuples/rows because sets don't allow duplicates. Thus, all relations are in 1NF because each tuple of a relation is unique.
This means all the three tables are in 1NF.
But if we go into language implementation, like SQL, then the answer would be language specific. For example, in SQL we would have 0 as answer because duplicate tuples are allowed in SQL. Go through this:
https://stackoverflow.com/questions/30767562/why-does-sql-standard-allow-duplicate-rows