A13210 | Cartoons

The first line contains single integer $t$ ( $1 \le t \le 1000$ ) — the number of test cases. The following are descriptions of the $t$ test cases.

The first line of each test case contains a single integer $n$ ( $1 \le n \le 2000$ ) — the number of cartoons.

In the next $n$ lines, the cartoons themselves are described, one per line, by a pair of integers $a_i$ , $b_i$ ( $1 \le a_i \le b_i \le 10^9$ ) — the first and last airing days for the $i$ -th cartoon.

It is guaranteed that the sum of the values $n$ for all test cases in the input does not exceed $2000$ .

Print $t$ answers to given test cases in the order in which they appear in the input: the $i$ -th answer is such $x$ , that only one cartoon will be airing on day $x$ or -1 if there are no such days.

In the third test case: at day $1$ and $2$ , first and third cartoons will be airing, and days $3$ and $4$ , second and third cartoons will be airing. So, there is no day when only one cartoon will be airing.

In the fourth test case, $11$ is also a possible answer.