In 'MonkeyLand', there is a traditional game called "Bamboo Climbing". The rules of the game are as follows:

1. There are N monkeys who play this game and there are N bamboos of equal heights. Let the height be L meters.
2. Each monkey stands in front of a bamboo and every monkey is assigned a different bamboo.
3. When the whistle is blown, the monkeys start climbing the bamboos and they are not allowed to jump to a different bamboo throughout the game.
4. Since they are monkeys, they usually climb by jumping. And in each jump, the i^th monkey can jump exactly p_i meters (p_i is a prime). After a while when a monkey finds that he cannot jump because one more jump may get him out of the bamboo, he reports the remaining length r_i that he is not able to cover.
5. And before the game, each monkey is assigned a distinct p_i.
6. The monkey, who has the lowest r_i, wins.

Now, the organizers have found all the information of the game last year, but unluckily they haven't found the height of the bamboo. To be more exact, they know N, all p_i and corresponding r_i, but not L. So, you came forward and found the task challenging and so, you want to find L, from the given information.

Input starts with an integer T (≤ 10000), denoting the number of test cases.

Each case starts with a line containing an integer n (1 ≤ n ≤ 12). Each of the next n lines contains two integers p_i (1 < p_i < 40, p_i is a prime) and r_i (0 < r_i < p_i). All p_i will be distinct.

For each case, print the case number and the minimum possible value of L that satisfies the above conditions. If there is no solution, print Impossible.