Table:
text: 1999–2000 Philadelphia Flyers season
Playoffs
Eastern Conference Semifinals
Game Date_ Opponent Score Series
1 April 27 Pittsburgh Penguins 0–2 Penguins lead 1–0
2 April 29 Pittsburgh Penguins 1–4 Penguins lead 2–0
3 May 2 @ Pittsburgh Penguins 4–3 OT Penguins lead 2–1
4 May 4 @ Pittsburgh Penguins 2–1 5OT Series tied 2–2
5 May 7 Pittsburgh Penguins 6–3 Flyers lead 3–2
6 May 9 @ Pittsburgh Penguins 2–1 Flyers win 4–2

Question: What was the Eastern Conference Semifinals, the playoff series that ended after Game 1 of the Philadelphia Flyers' 1999-2000 season?