Given two integers n and m. The problem is to find the number closest to n and divisible by m. If there are more than one such number, then output the one having maximum absolute value. If n is completely divisible by m(not equal to 0), then output n only. Time complexity of O(1) is required.
The first line consists of an integer T i.e number of test cases. The first and only line of each test case contains two space separated integers n and m.
Print the closest number to n which is also divisible by m.