Morton Numbers

The Morton number of two integers $x$ and $y$ is the integer built by interleaving the bits of $x$ and the bits of $y$ one place at a time. The bits of $x$ go to the even numbered places and the bits of $y$ go to the odd numbered places, where places are counted upward from the least significant bit, which is the first place.

Write $x_i$ for the $i$-th bit of $x$ and $y_i$ for the $i$-th bit of $y$, so that $x = \sum_{i=1}^{16} x_i 2^{i-1}$ and the same holds for $y$. The Morton number $M$ is then

$M = \sum_{i=1}^{16} \left( x_i \, 2^{2i-1} + y_i \, 2^{2i-2} \right)$

If $x$ and $y$ are read as the coordinates of a point in the plane, two points that lie close together have Morton numbers that lie close together as well. The Morton number also grows when $x$ or $y$ grows.

Given $x$ and $y$ in base 10, write a program that prints their Morton number in base 10.

The first line contains the integers $x$ and $y$ separated by whitespace. ($0 \le x, y \le 2^{16} - 1$)

Print the Morton number of $x$ and $y$ on the first line.