#include <cstdio>
using namespace std;

int people[50005];

/*查找根节点*/
int findRoot(int node){
	//自身不是自己的父节点的时候 
	while(people[node] != node){
		node = people[node];
	}
	return node;
}

int main(){
	int n, m, i,count, var1, var2, root1, root2, count1 = 1;
	while(scanf("%d %d", &n, &m) && (n!=0 || m!=0)){
		//最开始假设是每个人都有自己的信仰 
		count = n;
		//最开始每个人的父节点都是自己 
		for(i = 0; i < n; i++){
			people[i] = i;
		}
		
		while(m--){
			scanf("%d %d", &var1, &var2);
			root1 = findRoot(var1);
			root2 = findRoot(var2);
			//两个人的父节点不同,那么就减少一种信仰。 
			if(root1 != root2) {
				people[var1] = people[root1] = root2;
				count--;
			} 
		} 
		printf("Case %d: %d\n",count1++, count);
	}
	return 0;
}