Question: Not Alone, is Zhang Liyin's which number overall single, Zhang held a showcase to support the release of the single, which was held at the Century Theater in Beijing, EXO members Tao and Chen were guests, Exois a South Korean-Chinese boy group based in Seoul? 
Sentence (from "Exo (band)"): Exo's first album "XOXO" (2013), which contained the breakthrough hit "Growl", was a critical and commercial success, winning both Disk Daesang at the 28th Golden Disk Awards and Album of the Year at the 15th Mnet Asian Music Awards.
Relevant evidence: No