/*
*/

//#pragma comment(linker, "/STACK:16777216")
#define _CRT_SECURE_NO_WARNINGS
#include <fstream>
#include <iostream>
#include <string>
#include <complex>
#include <math.h>
#include <set>
#include <vector>
#include <map>
#include <queue>
#include <stdio.h>
#include <stack>
#include <algorithm>
#include <list>
#include <ctime>
#include <memory.h>
#include <assert.h>

#define y0 sdkfaslhagaklsldk
#define y1 aasdfasdfasdf
#define yn askfhwqriuperikldjk
#define j1 assdgsdgasghsf
#define tm sdfjahlfasfh
#define lr asgasgash
#define prev asdgasdgajshdhfs

#define eps 1e-8
//#define M_PI 3.141592653589793
#define bs 1000000007
#define bsize 256

const int N = 1250;

using namespace std;

int tests;
int prev[3][N], nxt[3][N], dp[N][N];
int board[3][N];
int ts, n;
string st;
int ni, nj;

int main(){
	//freopen("route.in","r",stdin);
	//freopen("route.out","w",stdout);
		freopen("F:/in.txt","r",stdin);
	freopen("F:/output.txt","w",stdout);
	ios_base::sync_with_stdio(0);
	//cin.tie(0);

	cin >> tests;
	for (; tests; --tests)
	{
		cin >> n;
		++ts;
		for (int i = 1; i <= 2; i++)
		{
			cin >> st;
			for (int j = 1; j <= n; j++)
			{
				if (st[j - 1] == 'X')
					board[i][j] = 1;
				else
					board[i][j] = 0;
			}
		}


		// prec
		nxt[1][n+1] = n + 1;
		nxt[2][n+1] = n + 1;
		for (int i = n; i; --i)
		{
			for (int j = 1; j <= 2; j++)
			{
				nxt[j][i] = nxt[j][i + 1];
				if (board[j][i] == 1)
					nxt[j][i] = i;
			}
		}

		for (int i = 1; i <= n; i++)
		{
			for (int j = 1; j <= 2; j++)
			{
				prev[j][i] = prev[j][i - 1];
				if (board[j][i] == 1)
					prev[j][i] = i;
			}
		}


		// dp

		for (int i = 0; i <= n; i++)
		{
			for (int j = 0; j <= n; j++)
			{
				dp[i][j] = 1e9;
			}
		}

		dp[0][0] = 0;

		for (int i = 0; i <= n; i++)
		{
			for (int j = 0; j <= n; j++)
			{
				if (board[1][i + 1] == 1)
					dp[i + 1][j] = min(dp[i + 1][j], dp[i][j]);
				if (board[2][j + 1] == 1)
					dp[i][j + 1] = min(dp[i][j + 1], dp[i][j]);

				//str8
				if (board[1][i + 1] == 0)
				{
					int ni = nxt[1][i+1] - 1;
					int nj = j;
					if (nj == i)
						nj++;
					dp[ni][nj] = min(dp[ni][nj], dp[i][j] + 1);
				}

				if (board[2][j + 1] == 0)
				{
					int nj = nxt[2][j+1] - 1;
					int ni = i;
					if (ni == j)
						ni++;
					dp[ni][nj] = min(dp[ni][nj], dp[i][j] + 1);
				}

				//cross

				if (i >= j&&prev[2][i+1] <= j)
				{
					dp[i + 1][nxt[2][i + 1]-1] = min(dp[i + 1][nxt[2][i + 1]-1], dp[i][j] + 1);
				}
				if (j >= i&&prev[1][j + 1] <= i)
				{
					dp[nxt[1][j + 1]-1][j + 1] = min(dp[nxt[1][j + 1]-1][j + 1], dp[i][j] + 1);
				}
			}
		}
		/*
		for (int i = 1; i <= n; i++)
		{
			for (int j = 1; j <= n; j++)
				cout << dp[i][j] << " ";
			cout << endl;
		}*/

//		cout << dp[12][8] << endl;

		cout << "Case #" << ts << ": " << dp[n][n] << endl;
	}

	cin.get(); cin.get();
	return 0;
}