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

Justiina has planned the event and created a list of dance pairs. The list consists of $n/2$ pairs, and each pupil belongs to exactly one pair.

However, Kotivalo has made a little prank and added somewhere in the list an extra pair. Your task is to find this pair.

**Input**

The first input line contains an integer $n$: the number of pupils.

After this, there are $n/2+1$ lines: Justiina's plan with Kotivalo's addition. Each line contains two distinct integers between $1,2,\ldots,n$.

**Output**

Print the line added by Kotivalo in the same way as in the input. You can assume that there is only one possible answer.

**Example**

Input:

`8`

7 3

6 4

4 8

2 5

6 1

Output:

`6 4`

**Subtask 1 (35 points)**

- $2 \le n \le 100$

**Subtask 2 (65 points)**

- $2 \le n \le 10^5$