B"William has two numbers a and b initially both equal to zero. William mastered performing three different operations with them quickly. Before performing each operation some positive integer k is picked, which is then used to perform one of the following operations: (note, that for each operation you can choose a new positive integer k ) Note that after performing operations, numbers a and b may become negative as well. William wants to find out the minimal number of operations he would have to perform to make a equal to his favorite number c and b equal to his second favorite number d . Each test contains multiple test cases. The first line contains the number of test cases t ( 1 <= t <= 10^4 ). Description of the test cases follows. The only line of each test case contains two integers c and d (0 <= c, d <= 10^9) , which are William's favorite numbers and which he wants a and b to be transformed into. For each test case output a single number, which is the minimal number of operations which William would have to perform to make a equal to c and b equal to d , or -1 if it is impossible to achieve this using the described operations. Let us demonstrate one of the suboptimal ways of getting a pair (3, 5) : "...