Largest Common Vertex on a Rooted Tree

A rooted tree has 1023 vertices. Vertex 1 is the root, and the two children of vertex $v$ are vertex $2v$ and vertex $2v+1$. Under this rule each natural number from 1 to 1023 is attached to exactly one vertex. Vertices numbered 512 to 1023 have no children. The top four levels look like this.

                1
        2               3
    4       5       6       7
  8   9   10  11  12  13  14  15

Let $M(a, b)$ be the largest vertex number that lies on both the path from vertex 1 to vertex $a$ and the path from vertex 1 to vertex $b$. For example, $M(4, 11) = 2$ and $M(7, 12) = 3$.

Given two natural numbers $A$ and $B$, let $M(A, B) = k$. Write a program that computes $10k$.

The first line contains the number of test cases $T$ ($1 \le T \le 50000$). Each of the next $T$ lines holds one test case: two integers $A$ and $B$ ($1 \le A, B \le 1023$, $A \ne B$) separated by a single space.

For each test case, print the value of $10k$ on its own line.