content: package v108;
  
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.Arrays;
  import java.util.StringTokenizer;
  
  public class ThunderMountain_UVa10803 {
  
  	
  	static final int INF = (int)1e8;
  	static double[][] adjMat;
  	static int V;
  	
  	static void floyd()
  	{
  		for(int k = 0; k < V; ++k)
  			for(int i = 0; i < V; ++i)
  				for(int j = 0; j < V; ++j)
  					adjMat[i][j] = Math.min(adjMat[i][j], adjMat[i][k] + adjMat[k][j]);
  	}
  	public static void main(String[] args) throws IOException {
  		
  		Scanner sc = new Scanner(System.in);
  		PrintWriter out = new PrintWriter(System.out);
  
  		int tc = sc.nextInt();
  		for(int t = 1; t <= tc; ++t)
  		{
  			V = sc.nextInt();
  			adjMat = new double[V][V];
  			for(int i = 0; i < V; ++i)
  			{
  				Arrays.fill(adjMat[i], INF);
  				adjMat[i][i] = 0.0;
  			}
  			
  			int[][] pos = new int[V][2];
  			for(int i = 0; i < V; ++i)
  			{
  				pos[i][0] = sc.nextInt();
  				pos[i][1] = sc.nextInt();
  			}
  			for(int i = 0; i < V; ++i)
  				for(int j = i + 1; j < V; ++j)
  				{
  					int x1 = pos[i][0], x2 = pos[j][0], y1 = pos[i][1], y2 = pos[j][1];
  					int d2 = (x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1);
  					if(d2 <= 100)
  						adjMat[i][j] = adjMat[j][i] = Math.sqrt(d2);
  				}
  			double max = 0;
  			floyd();
  			for(int i = 0; i < V; ++i)
  				for(int j = i + 1; j < V; ++j)
  					max = Math.max(max, adjMat[i][j]);
  			out.format("Case #%d:\n", t);
  			if(max > INF / 10)
  				out.println("Send Kurdy\n");
  			else
  				out.format("%.4f\n\n", max);
  			
  		}
  					
  		out.flush();
  
  	}
  	
  	static class Scanner 
  	{
  		StringTokenizer st;
  		BufferedReader br;
  
  		public Scanner(InputStream s){	br = new BufferedReader(new InputStreamReader(s));}
  
  		public String next() throws IOException 
  		{
  			while (st == null || !st.hasMoreTokens()) 
  				st = new StringTokenizer(br.readLine());
  			return st.nextToken();
  		}
  
  		public int nextInt() throws IOException {return Integer.parseInt(next());}
  		
  		public long nextLong() throws IOException {return Long.parseLong(next());}
  
  		public String nextLine() throws IOException {return br.readLine();}
  			
  		public boolean ready() throws IOException {return br.ready();}
  
  
  	}
  }
  