The smallest Topological Sort

Given a directed unweighted graph. Find its lexicographically smallest topological sorting.

Input

The first line contains two integers $n$ and $m(1\le n,m\le 10^5)$ — the number of vertices and edges in the graph. The next $m$ lines describe the edges of the graph. Each edge is given by a pair of integers — the starting and ending vertices.

Output

Print the lexicographically smallest topological sorting of the graph as a sequence of vertex numbers. If it is not possible to perform a topological sorting, print $-1$.

Examples