#include
     
       using namespace std; int father[50005]; int rank[50005]; int maxNum; void make_set(int x){
        father[x]=x;      rank[x]=1; } int find_set(int x){
   if(x!=father[x])      {
            father[x]=find_set(father[x]);      } return father[x]; } void Union(int x,int y){
       x=find_set(x);     y=find_set(y); if(x==y)  return; if(rank[x]<=rank[y]){
         father[x]=y;       rank[y]+=rank[x];       maxNum--;     //每合并一次总数减一     } else{
         father[y]=x;       rank[x]+=rank[y];       maxNum--;     }   } int main(){
   int m,n; int i,j; int x,y; int Case=1;     freopen("acm.txt","r",stdin);     cin>>n>>m; while(n){
          maxNum=n; for(i=n;i>0;i--)         make_set(i); for(j=m;j>0;j--){
           cin>>x>>y;         Union(x,y);       }       cout<<"Case "<
      
       <<": "<
       
        <
        
         >n>>m;       Case++;       } return 0; }