Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| No. in series | No. in season | Title | Directed by | Written by | Original air date | U.S. viewers (millions) |
| --- | --- | --- | --- | --- | --- | --- |
| 55.0 | 1.0 | "Take Two" | Mark Tinker | Craig Turk & Steve Blackman | September23,2010 | 9.02 |
| 56.0 | 2.0 | "Short Cuts" | Mark Tinker | Sonay Washington | September30,2010 | 7.93 |
| 57.0 | 3.0 | "Playing God" | Donna Deitch | Sheila Lawrence | October7,2010 | 7.90 |
| 58.0 | 4.0 | "A Better Place to Be" | Tom Verica | Barbie Kligman | October14,2010 | 8.07 |
| 59.0 | 5.0 | "In or Out" | Ed Ornelas | Ayanna A. Floyd | October21,2010 | 7.66 |
| 60.0 | 6.0 | "All in the Family" | Ann Kindberg | Sanford Golden & Karen Wyscarver | October28,2010 | 7.68 |
| 61.0 | 7.0 | "Did You Hear What Happened to Charlotte King?" | Allison Liddi-Brown | Shonda Rhimes | November4,2010 | 10.18 |
| 62.0 | 8.0 | "What Happens Next" | Michael Zinberg | Jennifer Cecil | November11,2010 | 8.21 |
| 63.0 | 9.0 | "Can't Find My Way Back Home" | Mark Tinker | Fred Einesman | November18,2010 | 8.01 |
| 64.0 | 10.0 | "Just Lose It" | Stephen Cragg | Elizabeth Klaviter | December2,2010 | 7.90 |
| 65.0 | 11.0 | "If You Don't Know Me By Now" | Eric Stoltz | Zahir McGhee | January6,2011 | 7.67 |
| 66.0 | 12.0 | "Heaven Can Wait" | Kenny Leon | Barbie Kligman | February3,2011 | 7.05 |
| 67.0 | 13.0 | "Blind Love" | Bethany Rooney | Craig Turk & Steve Blackman | February10,2011 | 7.26 |
| 68.0 | 14.0 | "Home Again" | Mark Tinker | Krista Vernoff | February17,2011 | 6.73 |
| 69.0 | 15.0 | "Two Steps Back" | Jeff Bleckner | Ayanna A. Floyd | February24,2011 | 6.44 |
| 70.0 | 16.0 | "Love and Lies" | Ann Kindberg | Moira McMahon | March17,2011 | 5.97 |
| 71.0 | 17.0 | "A Step Too Far" | Scott Printz | Fred Einesman | March24,2011 | 7.93 |
| 72.0 | 18.0 | "The Hardest Part" | Paul Adelstein | Jennifer Cecil | March31,2011 | 7.35 |
| 73.0 | 19.0 | "What We Have Here..." | Karen Gaviola | Christopher Fife | April28,2011 | 6.68 |
| 74.0 | 20.0 | "Something Old, Something New" | Mark Tinker | Sanford Golden & Karen Wyscarver | May5,2011 | 6.89 |
| 75.0 | 21.0 | "God Bless the Child" | Jeannot Szwarc | Jennifer Cecil & Barbie Kligman | May12,2011 | 7.27 |
Question:
What number episode in the season was directed by Paul Adelstein? 
Answer:
18.0