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**Task** | Statistics

Time limit: | 1.00 s | Memory limit: | 512 MB |

Given an undirected graph, your task is to choose a direction for each edge so that the resulting directed graph is acyclic.

The first input line has two integers $n$ and $m$: the number of nodes and edges. The nodes are numbered $1,2,\dots,n$.

After this, there are $m$ lines describing the edges. Each line has two distinct integers $a$ and $b$: there is an edge between nodes $a$ and $b$.

Print $m$ lines describing the directions of the edges. Each line has two integers $a$ and $b$: there is an edge from node $a$ to node $b$. You can print any valid solution.

- $1 \le n \le 10^5$

- $1 \le m \le 2 \cdot 10^5$

- $1 \le a,b \le n$

Input:

`3 3`

1 2

2 3

3 1

Output:

`1 2`

3 2

3 1