A ballet school is planning a performance in which the ballerinas will perform duets. There are 6 ballerinas: Andi, Benita, Chloe, Doris, Evelyn, Fatima. They will dance the following duets:  Andi ‐ Benita  Evelyn ‐ Doris  Andi ‐ Evelyn  Benita ‐ Chloe  Doris ‐ Andi  Fatima ‐ Benita Practical session Computational Thinking 2  Chloe ‐ Evelyn  Benita ‐ Doris  Doris ‐ Fatima  Fatima ‐ Evelyn

The ballet teacher wants to schedule the rehearsals for this afternoon with a time slot for each duet in such a way that, when changing from one rehearsal to the next, one of the dancers can remain for the next rehearsal.

However, no dancer can dance more than twice in a row as this is just too tiring.

E.g., when Andi and Evelyn have the first rehearsal slot, then the next rehearsal could be Chloe and Evelyn.

Which ballerina can not be in the first duet no matter what schedule the ballet teacher comes up with? - Provide explanation