#include <algorithm>

#include <cassert>

#include <cmath>

#include <cstdio>

#include <cstring>

#include <iostream>

#include <map>

#include <queue>

#include <set>

#include <tuple>

#define LOCAL_DEBUG

using namespace std;

typedef pair<double, int> MyPair;

const int MAXN = ;

int dx[] = { , -, ,  };

int dy[] = { , , , - };

char maze[MAXN][MAXN];

bool used[];

void fillin(int i, int j, int n) {

    memset(used, , sizeof used);

    for (int di = ; di < ; di++) {

        int tx = i + dx[di];

        int ty = j + dy[di];

        if ( > tx || tx >= n)continue;

        if ( > ty || ty >= n)continue;

        if (maze[tx][ty] == '.')continue;

        used[maze[tx][ty] - 'A'] = true;

    }

}

int main() {

#ifdef LOCAL_DEBUG

    freopen("C:\\Users\\Iris\\source\\repos\\ACM\\ACM\\input.txt", "r", stdin);

    //freopen("C:\\Users\\Iris\\source\\repos\\ACM\\ACM\\output.txt", "w", stdout);

#endif // LOCAL_DEBUG

    int T;

    scanf("%d", &T);

    for (int ti = ; ti <= T; ti++) {

        int n;

        scanf("%d", &n);

        for (int i = ; i < n; i++)scanf("%s", maze + i);

        for (int i = ; i < n; i++) {

            for (int j = ; j < n; j++) {

                if (maze[i][j] != '.')continue;

                fillin(i, j, n);

                for (char c = 'A'; c <= 'Z'; c++) {

                    if (!used[c - 'A']) {

                        maze[i][j] = c;

                        break;

                    }

                }

            }

        }

        printf("Case %d:\n", ti);

        for (int i = ; i < n; i++)printf("%s\n", maze[i]);

    }

    return ;

}