Topological Sort

Given a directed unweighted graph. Topologically sort its vertices.

Input

The first line contains the number of vertices $n(1\le n\le 10^5)$ and the number of edges $m(1\le m\le 10^5)$ in a graph. In the following $m$ lines, the edges of the graph are listed, each of which is defined by a pair of numbers — the indices of the starting and ending vertices.

Output

Print any topological sort of the graph as a sequence of vertex numbers. If the graph cannot be topologically sorted, then print $-1$.

Examples