CF2184C.Huge Pile

Andrei has a huge pile of $n$ apples. He can divide the pile into two smaller piles: if there are $x$ apples in the pile, he will get piles with $\lfloor \frac{x}{2} \rfloor$$^{\text{∗}}$ and $\lceil \frac{x}{2} \rceil$$^{\text{†}}$ apples. This division takes Andrei $1$ minute.

Andrei wants to eat $k$ apples, but he doesn't want to count them at all. That is why he wants to obtain a pile that contains exactly $k$ apples. Determine whether it is possible to achieve this by performing pile divisions. If it is possible, find the minimum possible time for Andrei to obtain a pile with exactly $k$ apples.

$^{\text{∗}}$$\lfloor \frac{x}{2} \rfloor$ — the largest integer $\le \frac{x}{2}$.

$^{\text{†}}$$\lceil \frac{x}{2} \rceil$ — the smallest integer $\ge \frac{x}{2}$.

安德烈有一大堆 $n$ 个苹果。他可以将一堆苹果分成两堆更小的苹果堆：若当前堆中有 $x$ 个苹果，则分出的两堆分别含有 $\lfloor \frac{x}{2} \rfloor$$^{\text{∗}}$ 和 $\lceil \frac{x}{2} \rceil$$^{\text{†}}$ 个苹果。每次分堆操作耗时 $1$ 分钟。

安德烈想吃掉 $k$ 个苹果，但他完全不想手动计数。因此，他希望得到一堆恰好含有 $k$ 个苹果的苹果堆。请判断是否能通过若干次分堆操作达成这一目标；若可以，请找出安德烈获得一堆恰好 $k$ 个苹果所需的最短时间。

$^{\text{∗}}$$\lfloor \frac{x}{2} \rfloor$ —— 表示不超过 $\frac{x}{2}$ 的最大整数。

$^{\text{†}}$$\lceil \frac{x}{2} \rceil$ —— 表示不小于 $\frac{x}{2}$ 的最小整数。

Each test consists of several test cases. The first line contains a single integer $t$ $(1 \le t \le 10^4)$ — the number of test cases. The following lines describe the test cases.

In the only line of each test case, two integers $n$ and $k$ are given — the number of apples in the huge pile and the number of apples that Andrei wants to obtain in one pile $(1 \le n, k \le 10^9)$.

每个测试包含若干测试用例。第一行包含一个整数 $t$（$1 \le t \le 10^4$）—— 测试用例的数量。接下来的行描述各个测试用例。

在每个测试用例的唯一一行中，给出两个整数 $n$ 和 $k$ —— 分别表示大堆中的苹果数量以及 Andrei 希望在一堆中获得的苹果数量（$1 \le n, k \le 10^9$）。

For each test case, output $-1$ if it is impossible to obtain a pile with exactly $k$ apples. Otherwise, output the minimum possible time required to obtain such a pile.

对于每个测试用例，如果无法得到恰好包含 $k$ 个苹果的堆，则输出 $-1$；否则，输出得到这样一堆苹果所需的最少时间。

In the first test case, after the first division, two piles of $5$ apples will be created. If one of them is divided, it will result in piles with $2$ and $3$ apples, so the answer is $2$.

In the second test case, if the pile is divided into two, it will result in piles with $5$ and $6$ apples, so the answer is $1$.

In the third test case, it is only possible to obtain piles with $1$, $2$, $3$, $5$, $6$, $10$, $11$, or $21$ apples, so the answer is $-1$.

在第一个测试用例中，第一次分割后会得到两堆苹果，每堆各有 $5$ 个。若再将其中一堆分割，则会产生分别含 $2$ 个和 $3$ 个苹果的两堆，因此答案为 $2$。

在第二个测试用例中，若将原堆分割为两堆，则会得到分别含 $5$ 个和 $6$ 个苹果的两堆，因此答案为 $1$。

在第三个测试用例中，仅可能得到含 $1$、$2$、$3$、$5$、$6$、$10$、$11$ 或 $21$ 个苹果的堆，因此答案为 $-1$。