#include <stdio.h>

int student[50001],n=0;
int count;

inline int read(void) {
	int x = 0;
	static char ch;
	while ((ch = getchar()) < '0' || (ch > '9'));
	x += ch - '0';
	while ((ch = getchar()) >= '0' && (ch <= '9')) {
		x *= 10;
		x += ch - '0';
	}
	return x;
}

inline int find(int x)
{
	while(student[x]!=x)
	{
		x=student[x];
	}
	return x;
}

void change(int x,int y)
{
	int i=0;
	int px=find(x),py=find(y);
	if(px!=py)
	{
		--count;
		student[px]=py;
	}
	return;
}

int main(void)
{
	int k=0,m=0;
	int i=0,x=0,y=0;

	while(scanf("%d%d",&n,&m)&&n+m)
	{
		for(i=1;i<=n;++i)
		{
			student[i]=i;
		}
		count=n;
		for(i=0;i<m;++i)
		{
			x = read();
                        y = read(); //scanf("%d%d",&x,&y);
			change(x,y);
		}	
		printf("Case %d: %d\n",++k,count);
	}
}