7407: Choose your own path(Problem J5)

The output will be two lines. The first line will contain Y if all pages are reachable, and N otherwise. 
The last line will contain a non-negative integer K, which is the shortest path a reader can take while reading this book. There will always be a finite shortest path.

3
2 2 3
0
1 1

Y
2

Every page is reachable, since from page 1, we can reach pages 2 and 3. The shortest path is the path 1 → 2, which contains two pages.