How many millions of U.S. viewers watched the episode directed by Allison Liddi-Brown? 
{'header': ['No. in series', 'No. in season', 'Title', 'Directed by', 'Written by', 'Original air date', 'U.S. viewers (millions)'], 'page_title': '', 'page_id': '', 'types': ['real', 'real', 'text', 'text', 'text', 'text', 'text'], 'id': '1-18102421-2', 'section_title': '', 'caption': '', 'rows': [['143', '1', '"Resurrection" (Part 2)', 'Joe Chappelle', "Barry O'Brien", 'September22,2008', '17.23'], ['144', '2', '"Won\'t Get Fueled Again"', 'Matt Earl Beesley', 'Corey Evett & Matt Partney', 'September29,2008', '14.35'], ['145', '3', '"And How Does That Make You Kill?"', 'Sam Hill', 'Tamara Jaron', 'October6,2008', '13.88'], ['146', '4', '"Raging Cannibal"', 'Gina Lamar', 'Brian Davidson', 'October13,2008', '13.22'], ['147', '5', '"Bombshell"', 'Eric Mirich', 'Marc Dube', 'October20,2008', '13.51'], ['148', '6', '"Wrecking Crew"', 'Joe Chappelle', 'Corey Miller', 'November3,2008', '12.74'], ['149', '7', '"Cheating Death"', 'Sam Hill', 'Krystal Houghton', 'November10,2008', '13.82'], ['150', '8', '"Gone Baby Gone"', 'Carey Meyer', 'Dominic Abeyta', 'November17,2008', '15.46'], ['151', '9', '"Power Trip"', 'Joe Chappelle', 'Corey Evett & Matt Partney', 'November24,2008', '14.33'], ['152', '10', '"The DeLuca Motel"', 'Gina Lamar', 'Sunil Nayar', 'December8,2008', '13.79'], ['153', '11', '"Tipping Point"', 'Marco Black', 'Brian Davidson', 'December15,2008', '14.56'], ['154', '12', '"Head Case"', 'Sam Hill', 'Tamara Jaron', 'January12,2009', '15.83'], ['155', '13', '"And They\'re Offed"', 'Matt Earl Beesley', "Barry O'Brien", 'January19,2009', '14.58'], ['156', '14', '"Smoke Gets in Your CSI\'s"', 'Joe Chappelle', 'Krystal Houghton', 'February2,2009', '16.10'], ['157', '15', '"Presumed Guilty"', 'Larry Detwiler', 'Corey Miller', 'February9,2009', '13.81'], ['158', '16', '"Sink or Swim"', 'Sam Hill', 'Marc Dube', 'March2,2009', '13.42'], ['159', '17', '"Divorce Party"', 'Karen Gaviola', 'Corey Evett & Matt Partney', 'March9,2009', '14.22'], ['160', '18', '"Flight Risk"', 'Joe Chappelle', 'Sunil Nayar', 'March16,2009', '13.61'], ['161', '19', '"Target Specific" (Part 1)', 'Sam Hill', 'Tamara Jaron', 'March23,2009', '13.67'], ['162', '20', '"Wolfe In Sheep\'s Clothing" (Part 2)', 'Carey Meyer', 'Krystal Houghton', 'March30,2009', '13.46'], ['163', '21', '"Chip/Tuck"', 'Allison Liddi-Brown', 'Brian Davidson', 'April13,2009', '13.39'], ['164', '22', '"Dead on Arrival"', 'Gina Lamar', 'Corey Miller', 'April27,2009', '12.12'], ['165', '23', '"Collateral Damage"', 'Sam Hill', 'Marc Dube', 'May4,2009', '13.72'], ['166', '24', '"Dissolved"', 'Matt Earl Beesley', 'Corey Evett & Matt Partney', 'May11,2009', '13.59']], 'name': 'table_18102421_2'}