Question: While Bang Eun-jin directed Perfect Number, which film was her directorial debut?
Sentence (from "Perfect Number (film)"): Adapted from Keigo Higashino's novel "The Devotion of Suspect X", it centers around a mild-mannered mathematics teacher (Ryoo Seung-bum) who plans the perfect alibi for the woman he secretly loves (Lee Yo-won) when she unexpectedly murders her abusive ex-husband.
Relevant evidence: No