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http://acm.fzu.edu.cn/problem.php?pid=2150 

#include<stdio.h>
#include<iostream>
#include<math.h>
#include<stdlib.h>
#include<ctype.h>
#include<algorithm>
#include<vector>
#include<string.h>
#include<queue>
#include<stack>
#include<set>
#include<map>
#include<sstream>
#include<time.h>
#include<utility>
#include<malloc.h>

using namespace std;

int t, n, m;
char b[15][15];
int dir[4][2] = { { -1, 0 }, { 1, 0 }, { 0, 1 }, { 0, -1 } };
int vis[15][15];
int check(int x, int y)
{
    if (x >= 0 && x < n && y >= 0 && y < m)
        return 1;
    return 0;
}
struct node
{
    int x;
    int y;
    int t;
}q[150];

queue<node> de;
int step = 0;

int main()
{
    scanf("%d",&t);
    int c = 1;
    while (t--)
    {
        scanf("%d%d", &n, &m);
        for (int i = 0; i < n; i++)
            scanf("%s",b[i]);

        int num = 0;
        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++)
            {
                if (b[i][j] == '#')
                {
                    q[num].x = i;
                    q[num++].y = j;
                }
            }

        int ans = 0x3f3f3f3f;
        if (num == 2)
            ans = 0;
        else 
        for (int i = 0; i < num; i++)
        {
            for (int j = i; j < num; j++)
            {
                int sx = q[i].x;
                int sy = q[i].y;
                int ex = q[j].x;
                int ey = q[j].y;
                {

                    while (!de.empty()) de.pop();

                    node qq, qqq;
                    qq.x = sx; qq.y = sy; qq.t = 0;
                    qqq.x = ex; qqq.y = ey; qqq.t = 0;

                    de.push(qq);
                    de.push(qqq);
                    memset(vis,0,sizeof(vis));

                    vis[sx][sy] = vis[ex][ey] = 1;

                    step = 0;

                    /////////////////
                    while (!de.empty())
                    {
                        node qq = de.front();
                        de.pop();
                            step = qq.t;
                        for (int i = 0; i < 4; i++)
                        {
                            int x = qq.x + dir[i][0];
                            int y = qq.y + dir[i][1];

                            if (!check(x, y) || vis[x][y] || b[x][y] == '.')
                                continue;
                            node qqq;
                            qqq.x = x;
                            qqq.y = y;
                            qqq.t = qq.t + 1;
                            vis[x][y] = 1;
                            de.push(qqq);
                        }
                    }
                    ////////////////
                    int ok = 1;

                    for (int i = 0; i < n; i++)
                    {
                        for (int j = 0; j < m; j++)
                        {
                            if (vis[i][j] == 0 && b[i][j] == '#')
                            {
                                ok = 0;
                                break;
                            }
                        }
                    }

                    if (ok)
                    {
                        ans = min(ans, step);
                    }
                }
            }
        }
        if (ans == 0x3f3f3f3f)
            ans = -1;
        printf("Case %d: %d\n",c++,ans);
    }
}