CF1680E.Moving Chips

You are given a board of size $2 \times n$ ($2$ rows, $n$ columns). Some cells of the board contain chips. The chip is represented as '*', and an empty space is represented as '.'. It is guaranteed that there is at least one chip on the board.

In one move, you can choose any chip and move it to any adjacent (by side) cell of the board (if this cell is inside the board). It means that if the chip is in the first row, you can move it left, right or down (but it shouldn't leave the board). Same, if the chip is in the second row, you can move it left, right or up.

If the chip moves to the cell with another chip, the chip in the destination cell disappears (i. e. our chip captures it).

Your task is to calculate the minimum number of moves required to leave exactly one chip on the board.

You have to answer $t$ independent test cases.

你有一个大小为 $2 \times n$（2 行，$n$ 列）的棋盘。棋盘上某些格子中放置有棋子。棋子用字符 * 表示，空格用字符 . 表示。保证棋盘上至少有一个棋子。

在一次操作中，你可以任选一个棋子，并将其移动到棋盘上与其相邻（共享一条边） 的任意一个格子中（前提是该格子仍在棋盘范围内）。也就是说，若棋子位于第一行，则可向左、向右或向下移动（但不能移出棋盘）；若棋子位于第二行，则可向左、向右或向上移动。

当一个棋子移动到另一个棋子所在的格子时，目标格子中的棋子将被移除（即：该棋子“吃掉”了目标棋子）。

你的任务是计算：使得棋盘上最终恰好只剩一个棋子所需的最少操作次数。

你需要回答 $t$ 个相互独立的测试用例。

The first line of the input contains one integer $t$ ($1 \le t \le 2 \cdot 10^4$) — the number of test cases. Then $t$ test cases follow.

The first line of the test case contains one integer $n$ ($1 \le n \le 2 \cdot 10^5$) — the length of the board. The second line of the test case contains the string $s_1$ consisting of $n$ characters '*' (chip) and/or '.' (empty cell). The third line of the test case contains the string $s_2$ consisting of $n$ characters '*' (chip) and/or '.' (empty cell).

Additional constraints on the input:

• in each test case, there is at least one chip on a board;
• the sum of $n$ over all test cases does not exceed $2 \cdot 10^5$ ($\sum n \le 2 \cdot 10^5$).

输入的第一行包含一个整数 $t$（$1 \le t \le 2 \cdot 10^4$），表示测试用例的数量。随后是 $t$ 个测试用例。

每个测试用例的第一行包含一个整数 $n$（$1 \le n \le 2 \cdot 10^5$），表示棋盘的长度。
每个测试用例的第二行包含一个长度为 $n$ 的字符串 $s_1$，由字符 '*'（棋子）和/或 '.'（空格）组成。
每个测试用例的第三行包含一个长度为 $n$ 的字符串 $s_2$，由字符 '*'（棋子）和/或 '.'（空格）组成。

输入的额外约束条件：

• 每个测试用例中，棋盘上至少有一个棋子；
• 所有测试用例的 $n$ 值之和不超过 $2 \cdot 10^5$（即 $\sum n \le 2 \cdot 10^5$）。

For each test case, print one integer — the minimum number of moves required to leave exactly one chip on the board.

对于每个测试用例，输出一个整数——使棋盘上恰好剩余一枚芯片所需的最少移动次数。