B'You are given a grid with n rows and m columns. Rows and columns are numbered from 1 to n , and from 1 to m . The intersection of the a -th row and b -th column is denoted by (a, b) . Initially, you are standing in the top left corner (1, 1) . Your goal is to reach the bottom right corner (n, m) . You can move in four directions from (a, b) : up to (a-1, b) , down to (a+1, b) , left to (a, b-1) or right to (a, b+1) . You cannot move in the same direction in two consecutive moves, and you cannot leave the grid. What is the minimum number of moves to reach (n, m) ? The input consists of multiple test cases. The first line contains a single integer t ( 1 <= t <= 10^3 ) -- the number of the test cases. The description of the test cases follows. The first line of each test case contains two integers n and m ( 1 <= n, m <= 10^9 ) -- the size of the grid. For each test case, print a single integer: -1 if it is impossible to reach (n, m) under the given conditions, otherwise the minimum number of moves. Test case 1 : n=1 , m=1 , and initially you are standing in (1, 1) so 0 move is required to reach (n, m) = (1, 1) . Test case 2 : you should go down to reach (2, 1) . Test case 3 : it is impossible to reach (1, 3) without moving right two consecutive times, or without leaving the grid. Test case 4 : an optimal moving sequence could be: (1, 1) to (1, 2) to (2, 2) to (2, 1) to (3, 1) to (3, 2) to (4, 2) . It can be proved that this is the optimal solution. So the answer is 6 . '...