d813

/* d813             */
/* AC (0.1s, 336KB) */
#include <cstdio>
#include <cstring>

using namespace std;

int relation[50010];

int _find(int _p)
{
    if(relation[_p] == _p) return _p;
    else return relation[_p] = _find(relation[_p]);
}

int main()
{
    for(int n, m, t = 1, cnt = 0; ~scanf("%d %d", &n, &m) && (n || m); ++t, cnt = 0)
    {
        bool relate[50010];
        memset(relate, false, sizeof(relate));
        for(int i = 1; i <= n; relation[i] = i, ++i);

        for(int c = 0, i, j; c < m && scanf("%d %d", &i, &j); ++c, relation[_find(i)] = _find(j));

        for(int i = 1; i <= n; ++i)
            if(!relate[_find(i)]){ cnt++; relate[_find(i)] = true; }
        printf("Case %d: %d\n", t, cnt);
    }
    return 0;
}