#include <iostream>

#include <vector>

#include <map>

#include <stack>

#include <algorithm>

using namespace std;

map<string, vector<string>> G;

map<string, int> dfn, low;

vector<string> V;

int dep;

void dfs(string u)

{

    low[u] = dfn[u] = ++dep;

    V.emplace_back(u);

    for (auto& v : G[u])

        if (!dfn[v]) dfs(v), low[u] = min(low[u], low[v]);

        else if (count(V.begin(), V.end(), v)) low[u] = min(low[u], dfn[v]);

    if (dfn[u] == low[u])

    {

        string temp;

        while (1)

        {

            temp = V[V.size() - 1];

            V.pop_back();

            cout << temp;

            if (temp != u) cout << ", ";

            else break;

        }

        cout << "\n";

    }

}

int main()

{

    // fast io

    ios::sync_with_stdio(false);

    cin.tie(nullptr);

    cout.tie(nullptr);

    int n, m, cases = 0;

    while (cin >> n >> m, n && m) 

    {

        // init

        G.clear(), dfn.clear(), low.clear(), V.clear();

        dep = 0;

        // store data

        while (m--)

        {

            string name, to;

            cin >> name >> to;

            G[name].emplace_back(to);

        }

        // find scc

        if (cases) cout << "\n";

        cout << "Calling circles for data set " << ++cases << ":\n";

        for (auto& [i, j] : G) if (!dfn[i]) dfs(i);	

    }

    return 0;

}