Given a directed graph, print all vertices of the tree. When there is more than one vertex connect to visiting vertices, prioritize to visit the smaller nodes first.

Input

• The first line consists of two positive integers, the number of vertices ~n~ ~(0 < n \le 10^5)~ and the number of edges ~m~ ~(0 < m \le2 \times 10^5)~.
• Then there are ~m~ lines, each containing two integers ~u~ and ~v~ ~(u, v < 10^5)~, representing the direction from ~u~ to ~v~.

Output

• The list of vertices in the required order, separated by spaces.

Example Input:

4 4
0 3
3 2
1 0
0 1

Example Output:

0 1 3 2