Clockwise Murder

There are $N$ people standing in a circle labeled 1 through $N$, such that the smallest power of two less than or equal to $N$ is $X$. Starting with the person 1, they take a sword and kill the person to their left. Then, they pass the sword to the living person on their left, and the process continues until one person is left. The survivor's number can be expressed as $aN + bX + c$. Compute $a + 2b + 3c$.