- 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.
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 $1,2,\ldots,n$.
Print the line added by Kotivalo in the same way as in the input. You can assume that there is only one possible answer.
Subtask 1 (35 points)
- $2 \le n \le 100$
- $2 \le n \le 10^5$