// Author: btjanaka (Bryon Tjanaka)

// Problem: (UVa) 10583

#include <bits/stdc++.h>

#define GET(x) scanf("%d", &x)

#define GED(x) scanf("%lf", &x)

typedef long long ll;

using namespace std;

typedef pair<int, int> ii;

struct UnionFind {

vector<int> p, rank;

UnionFind(int n) : p(n), rank(n, 0) { iota(p.begin(), p.end(), 0); }

int find(int i) { return p[i] == i ? i : (p[i] = find(p[i])); }

bool same(int i, int j) { return find(i) == find(j); }

void join(int i, int j) {

if (!same(i, j)) {

int x = find(i), y = find(j);

if (rank[x] < rank[y]) {

p[x] = y;

} else {

p[y] = x;

if (rank[x] == rank[y]) ++rank[x];

}

}

}

int countp() {

unordered_set<int> ps;

for (int i = 0; i < p.size(); ++i) ps.insert(find(i));

return (int)ps.size();

}

};

int main() {

int n, m;

for (int ca = 1; GET(n) && GET(m) && (n || m); ++ca) {

int a, b;

UnionFind uf(n);

for (int i = 0; i < m; ++i) {

GET(a);

GET(b);

uf.join(a - 1, b - 1);

}

printf("Case %d: %d\n", ca, uf.countp());

}

return 0;

}