# Topological Sort

Very easy

Execution time limit is 2 seconds

Runtime memory usage limit is 128 megabytes

Given a directed unweighted graph. Topologically sort its vertices.

## Input

The first line contains the number of vertices $n(1≤n≤10_{5})$ and the number of edges $m(1≤m≤10_{5})$ 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

Input #1

Answer #1

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