bit setting

Program accept two integer $N$ and $M$ . where $N$ equals to number of bits and $M$ equals to number of set bits. implement the program to find the sum of all number possible from $N$ bits having the count of set bits equal to $M$ . ###Input: - First line will contain $T$ , number of testcases. - Each testcase contains a single line of input, two integers $N$ , $M$ . ###Output: For each t