P12353 DataErr0r

> How do you know you are not a Program?

For two binary strings $S$, $T$ (consisting of $0$ and $1$) of length $n$ and length $n+1$. You can perform the following types of operations: 1. Remove any bit from $T$. 2. Choose $1\le l \le r \le T$. For every $i$ satisfying $l\leq i\leq r$ and $l\equiv i \pmod 2$, let $T_i\gets 1-T_i$. You need to find the minimum number of operations to make $T=S$.

Each test consists of multiple test cases. The first line contains a single integer $t(1\leq t\leq 10^4)$ --- the number of sets of test cases. The description of test cases follows. The first line of each test case contains a single integer $n(1\leq n \leq 10^5)$ --- the length of $T$. The second line contains a single string $S$ with size $n+1$. The third line contains a single string $T$ with size $n$. It is guaranteed that the sum of $n$ does not exceed $2\cdot 10^5$.

For each test case, output a single number, containing the answer to how many operations are needed at least to make all digits the same for $S$ and $T$.

For the first sample, we can do operations below: - $1\textbf 01\textbf 01\to 11111$ - $111\underline1\to 111$ So we need $2$ operations. ### Constraints **This problem uses subtasks.** - Subtask 0 (15 pts): $1\leq \sum N\leq 10$. - Subtask 1 (35 pts): $1\leq \sum N\leq 10^3$. - Subtask 2 (50 pts): No additional constraints. It is guaranteed that $1\leq K\leq 1000$, $1\leq \sum N\leq 10^6$, $1\leq N\le 10^6$.