Let E be a given directed edge set. Suppose it is known that the edges in E can form a directed tree T with all the nodes (except the root node) has only 1 in-degree. The problem is how to efficiently traverse the edge set E, in order to find all the paths in T? 

For example, Given a directed edge set E={(1,2),(1,5),(5,6),(1,4),(2,3)}. We know that such a set E can generate a directed tree T with only 1 in-degree (except the root node). Is there any fast method to traverse the edge set E, in order to find all the paths as follows:

```
Path1 = {(1,2),(2,3)}
Path2 = {(1,4)}
Path3 = {(1,5),(5,6)}

```

By the way, suppose the number of edges in E is |E|, is there complexity bound to find all the paths?