- Time limit: 2.00 s
- Memory limit: 512 MB
Uolevi is going for a run in the forest. There are landmarks in the forest numbered and there is a bidirectional path between every pair of landmarks. Uolevi starts at landmark and wants to visit his favorite landmark . However, in the past he has run into snakes times. The -th snake appeared on a path between locations and . Uolevi is scared of snakes so he will not use these paths. Help Uolevi find a snakeless route to landmark or report that no such route exists. If there are multiple answers, print any.
Input
The first line contains two integers and . The -th of next lines contains two integers and .
Output
In the first line, print the number of landmarks Uolevi visits on his path to or if there is no such path. If there exists a path then print the landmarks on the path to in the order Uolevi visits them on the second line separated with space as below:
If there are multiple answers, print any.
Constraints
- if
Example 1
Input:
5 5 1 2 1 3 1 5 2 5 3 5
Output:
3 1 4 5
Example 2
Input:
5 7 1 2 1 3 1 4 1 5 2 3 2 4 2 5
Output:
0