4 Walls
... that 4 Walls was the first release by girl group f(x) since member Sulli left the group?
... that <i id="mwB7M"><b id="mwB7Q"><a href="./4_Walls" id="mwB7U" rel="mw:WikiLink" title="4 Walls">4 Walls</a></b></i> was the first release by girl group <a class="mw-redirect" href="./F(x)_(band)" id="mwB7Y" rel="mw:WikiLink" title="F(x) (band)">f(x)</a> since member <a href="./Sulli" id="mwB7c" rel="mw:WikiLink" title="Sulli">Sulli</a> left the group?