Topological Sort

Input

The first line contains two integers: the number of vertices $n$ (1 \le n \le 10^5) and the number of edges $m$ (1 \le m \le 10^5) in the graph. The following $m$ lines describe the edges of the graph, each given by a pair of integers: the start and end vertex numbers.

Output

If a topological sort of the graph is possible, print any valid topological ordering of the vertices as a sequence of their numbers. If the graph cannot be topologically sorted, print $-1$.

Examples