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:
| Game | Date | Opponent | Score | Series |
| --- | --- | --- | --- | --- |
| 1.0 | April 17 | @ Pittsburgh Penguins | 3–4 | Penguins lead 1–0 |
| 2.0 | April 19 | @ Pittsburgh Penguins | 4–2 | Series tied 1–1 |
| 3.0 | April 21 | Pittsburgh Penguins | 3–4 OT | Penguins lead 2–1 |
| 4.0 | April 23 | Pittsburgh Penguins | 4–1 | Series tied 2–2 |
| 5.0 | April 25 | @ Pittsburgh Penguins | 7–10 | Penguins lead 3–2 |
| 6.0 | April 27 | Pittsburgh Penguins | 6–2 | Series tied 3–3 |
| 7.0 | April 29 | @ Pittsburgh Penguins | 4–1 | Flyers win 4–3 |
Question:
What is the highest game that has april 21 as the date?
Answer:
3.0