content: package v105;
  
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.StringTokenizer;
  
  public class UbiquitousReligions_UVa10583 {
  	
  	public static void main(String[] args) throws IOException {
  		
  		Scanner sc = new Scanner(System.in);
  		PrintWriter out = new PrintWriter(System.out);
  		
  		int tc = 1;
  		while(true)
  		{
  			int n = sc.nextInt(), m = sc.nextInt();
  			if(n == 0)
  				break;
  			UnionFind uf = new UnionFind(n);
  			while(m-->0)
  				uf.unionSet(sc.nextInt() - 1, sc.nextInt() - 1);
  			out.format("Case %d: %d\n", tc++, uf.numDisjointSets());
  		}
  		out.flush();
  	}
  	
  	static class UnionFind {                                              
  		int[] p, rank, setSize;
  		int numSets;
  		
  		public UnionFind(int N) 
  		{
  			 p = new int[N];
  			 rank = new int[N];
  			 setSize = new int[N];
  			 numSets = N;
  			 for (int i = 0; i < N; i++) {  p[i] = i; setSize[i] = 1; }
  		}
  		
  		public int findSet(int i) 
  		{ 
  			if (p[i] == i) return i;
  			else return p[i] = findSet(p[i]);
  		 }
  		
  		public Boolean isSameSet(int i, int j) { return findSet(i) == findSet(j); }
  		
  		public void unionSet(int i, int j) 
  		{ 
  			 if (isSameSet(i, j)) 
  				 return;
  			 numSets--; 
  			 int x = findSet(i), y = findSet(j);
  			 // rank is used to keep the tree short
  			 if (rank[x] > rank[y]) { p[y] = x; setSize[x] += setSize[y]; }
  			 else
  			 {	p[x] = y; setSize[y] += setSize[x];
  			 	if(rank[x] == rank[y]) rank[y]++; 
  			 } 
  		}
  		
  		public int numDisjointSets() { return numSets; }
  		
  		public int sizeOfSet(int i) { return setSize[findSet(i)]; }
  	}
  	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 double nextDouble() throws IOException
  		{
  			String x = next();
  			StringBuilder sb = new StringBuilder("0");
  			double res = 0, f = 1;
  			boolean dec = false, neg = false;
  			int start = 0;
  			if(x.charAt(0) == '-')
  			{
  				neg = true;
  				start++;
  			}
  			for(int i = start; i < x.length(); i++)
  				if(x.charAt(i) == '.')
  				{
  					res = Long.parseLong(sb.toString());
  					sb = new StringBuilder("0");
  					dec = true;
  				}
  				else
  				{
  					sb.append(x.charAt(i));
  					if(dec)
  						f *= 10;
  				}
  			res += Long.parseLong(sb.toString()) / f;
  			return res * (neg?-1:1);
  		}
  		
  		public boolean nxtEmpty() throws IOException
  		{
  			String line = br.readLine();
  			if(line.isEmpty())
  				return true;
  			st = new StringTokenizer(line);
  			return false;
  		}
  		
  		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();}
  
  
  	}
  }
  