Question: The series, When a Man Falls in Love, starring South Korean actor Song Seung-heon was on air for how many episodes?
Context: My Princess () is a 2011 South Korean romantic comedy television series, starring Song Seung-heon, Kim Tae-hee, Park Ye-jin, and Ryu Soo-young.  It aired on MBC from January 5 to February 24, 2011 on Wednesdays and Thursdays at 21:55 for 16 episodes. Happy Together () is a 1999 South Korean television series starring Lee Byung-hun, Song Seung-heon, Kim Ha-neul, Jo Min-su, and Jun Ji-hyun It aired on SBS from June 16 to August 5, 1999 on Wednesdays and Thursdays at 21:55 for 16 episodes.  Starring young actors who would go on to become Korean TV and film stars, the hit drama revolves around five children who were separated at the death of their parents, and the love, conflicts, and reconciliation that these siblings go through when they meet again as adults. Dr. Jin () is a 2012 South Korean historical television drama series, starring Song Seung-heon in the title role of Dr. Jin, a 21st-century neurosurgeon who travels back in time to the Joseon Dynasty.  Also starring Park Min-young, Lee Beom-soo, Kim Jaejoong of JYJ and Lee So-yeon, it aired on MBC from May 26 to August 12, 2012 on Saturdays and Sundays at 21:50 for 22 episodes. Song Seung-heon (; born October 5, 1976) is a South Korean actor. Autumn in My Heart (; also known as Autumn Fairy Tale or Autumn Tale) is a 2000 South Korean romantic television drama, starring Song Seung-heon, Song Hye-kyo and Won Bin.  The series is the first installment of season-themed tetralogy "Endless Love" drama series directed by Yoon Seok-ho.  It aired on KBS2 from September 18 to November 7, 2000, on Mondays and Tuesdays for 16 episodes. Summer Scent () is a 2003 South Korean television series starring Song Seung-heon, Son Ye-jin, Ryu Jin, and Han Ji-hye.  It aired on KBS2 from July 7 to September 9, 2003 on Mondays and Tuesdays at 21:55 for 20 episodes. When a Man Falls in Love () is a 2013 South Korean television series, starring Song Seung-heon, Shin Se-kyung, Chae Jung-an, and Yeon Woo-jin.  The story revolves around a world-weary gangster as his love life intertwines with three others, and how the course of their lives changes entirely based on one moment of fevered passion.  It aired on MBC from April 3 to June 6, 2013 on Wednesdays and Thursdays at 21:55 for 20 episodes. Baek Min-hyun (born January 12, 1985) is a South Korean actor.  Baek, also known as "little Song Seung-heon", made his acting debut with the television drama "My Beloved Sister" (2006).  He starred in the film "Arang" (2006) and has also appeared in numerous commercials. East of Eden () is a 2008 South Korean television series, starring Song Seung-heon, Yeon Jung-hoon, Park Hae-jin, Lee Da-hae, Han Ji-hye, and Lee Yeon-hee.  It was produced by Chorokbaem Media as a 47th Anniversary Special Project Drama for MBC, on which it aired from August 25, 2008 to March 10, 2009 on Mondays and Tuesdays at 21:55 for 56 episodes.  The ₩25 billion drama tells the story of the brothers Dong-chul (Song) and Dong-wook (Yeon).  Their fates diverge after the murder of their coal miner father, with one joining the mob and the other becoming a successful lawyer. Black () is an upcoming fantasy-thriller South Korean television series starring Song Seung-heon, Go Ara, Lee El and Kim Dong-jun.  It is set to air on OCN starting October 14, 2017 on Saturdays and Sundays at 22:20 (KST) time slot, replacing "Save Me".
Answer: 20