//https://vjudge.net/contest/65959#problem/I
#include <iostream>
#include <vector>
#include <cstring>
#include <queue>
using namespace std;
typedef long long LL;
const int N = 15;
int dx[5] = {0,0,1,-1};
int dy[5] = {1,-1,0,0};
struct Node
{
int x,y;
int cnt ;
};
vector<Node> v;
char mp[N][N];
int vis[N][N];
int n,m;
int BFS(Node a,Node b)
{
memset(vis,0,sizeof(vis));
queue<Node> q;
vis[a.x][a.y] = vis[b.x][b.y] = 1;
a.cnt = 0,b.cnt = 0;
q.push(a),q.push(b);
int ans = 0x3f3f3f3f;
int cas = 1;
while(!q.empty())
{
a = q.front();
q.pop();
//printf("%d %d %d\n",a.x,a.y,a.cnt);
ans = a.cnt;
for(int i = 0;i<4;i++)
{
b.x = a.x + dx[i];
b.y = a.y + dy[i];
b.cnt = a.cnt + 1;
//printf("B:%d %d %d\n",b.x,b.y,b.cnt);
if(b.x>0 && b.y>0 && b.x<=n && b.y<=m && vis[b.x][b.y]==0 && mp[b.x][b.y]=='#')
{
vis[b.x][b.y] = 1;
q.push(b);
}
}
}
return ans;
}
void print()
{
for(int i=1;i<=n;i++)
{
for(int j = 1;j<=m;j++)
{
printf("%c ",mp[i][j]);
}
puts("");
}
}
int main()
{
//freopen("Input.txt","r",stdin);
int T;
scanf("%d",&T);
for(int cas=1;cas<=T;cas++)
{
v.clear();
scanf("%d%d",&n,&m);
for(int i=1;i<=n;i++)
{
getchar();
for(int j=1;j<=m;j++){
scanf("%c",&mp[i][j]);
if(mp[i][j]=='#')
v.push_back((Node){i,j,0});
}
}
int ans = 0x3f3f3f3f;
for(int i=0;i<v.size();i++)
{
for(int j=i;j<v.size();j++)
{
int tmp = BFS(v[i],v[j]);
bool ok = true;
for(int k = 1;k<=n;k++)
{
for(int f = 1;f<=m;f++)
{
if(vis[k][f] == 0 && mp[k][f]=='#')
{
ok = false;
break;
}
}
if(ok==false)
break;
}
if(ok)
{
ans = min(ans,tmp);
}
}
}
printf("Case %d: ",cas);
if(ans == 0x3f3f3f3f)
puts("-1");
else
printf("%d\n",ans);
}
return 0;
}