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

**Input**

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 integers $a$ and $b$: there is an edge between nodes $a$ and $b$.

You may assume that the graph is simple, i.e., there is at most one edge between any two nodes and every edge connects two distinct nodes.

**Output**

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.

If there are no solutions, only print "IMPOSSIBLE".

**Constraints**

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

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

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

**Example**

Input:

`4 4`

1 2

2 3

3 4

1 4

Output:

`1 2`

3 2

3 4

1 4