Sohel sir gave an assignment in CSE-315 course instead of a class test. The assignment was to make questions and provide corresponding answers from the chapters 2, 3, 4, 5. Each student is assigned chapter no y according to the formula: y = (Roll % 4) + 2 I.e. he has to make questions and answers from chapter y. According to this rule, Roll 4 was supposed to make questions and answers from chapter 2 as (4 % 4) + 2 = 2 and Roll 35 was assigned to chapter 5 as (35 % 4) +2 = 5. In the meantime, roll 35 had already made the questions & answers from chapter 5 and Roll 4 got the complete assignment of roll 35. So to copy that assignment Roll 4 wanted to change the divisor 4 of the formula to some number m such that his assignment changes to chapter 5 , that is (4 % m) + 2 = 5. But he failed to find such number. Now, your problem is similar to the above problem. Giventwonumberxandyyouhavetofindapositivenumbermsuchthat(x%m)+2=y. If multiple m is possible, choose the minimum one. If no answer is found print ‘Impossible’. Input First line of input will contain the number of test cases, T ≤ 125. Then there follows T lines, each containing two integers x (0 ≤ x ≤ 1012) and y (2 ≤ y ≤ x + 2). Output For each case, print m, if m is found. Otherwise print ‘Impossible’ (without quotes). See the samples given below for exact formatting. Sample Input 4 45 35 5 42 11 5 Sample Output Impossible 4 1 4