#include <bits/stdc++.h>

#define inf 0x3f3f3f3f

#define MAX 1000000000

#define FRE() freopen("in.txt","r",stdin)

#define FRO() freopen("out.txt","w",stdout)

using namespace std;

typedef long long ll;

typedef pair<int,ll> pii;

const int maxn = ;

int n,m,cnt;

map<string,int> idx;

string name1,name2;

string st[maxn];

int mp[maxn][maxn],vis[maxn];

int id(string name){

    if(!idx.count(name)){

        idx[name] = cnt;

        st[cnt] = name;

        return cnt++;

    }

    return idx[name];

}

int main(){

    //FRE();

    int kase = ;

    while(scanf("%d%d",&n,&m) && n){

        memset(mp,,sizeof(mp));

        memset(vis,,sizeof(vis));

        idx.clear();

        cnt=;

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

            cin>>name1>>name2;

            int p = id(name1),q = id(name2);

            mp[p][q] = ;

        }

        for(int k=; k<n; k++){

            for(int i=; i<n; i++){

                for(int j=; j<n; j++){

                    mp[i][j] = mp[i][j]||(mp[i][k]&&mp[k][j]);

                }

            }

        }

        if(kase)cout<<endl;

        cout<<"Calling circles for data set "<<++kase<<":"<<endl;

        for(int i=; i<n; i++){

            if(vis[i]==){

                cout<<st[i];

                vis[i] = ;

                for(int j=i+; j<n; j++){

                    if(vis[j]==&&mp[i][j]&&mp[j][i]){

                        cout<<", "<<st[j];

                        vis[j]=;

                    }

                }

                cout<<endl;

            }

        }

    }

    return ;

}