dfs_string_map

#include<bits/stdc++.h>
using namespace std;

#define     rep(i,k,n)      for(long long int i=k;i<n;i++)
#define     fast            ios_base::sync_with_stdio(false);cin.tie(NULL)
#define     read            freopen("input.txt","r",stdin)
#define     write           freopen("output.txt","w",stdout)
#define     D(x)            cout << '>' << #x << ':' << x << endl
#define     DD(x,y)         cout << '>' << #x << ':' << x << ' ' << #y << ':' << y << endl
#define     DDD(x,y,z)      cout << '>' << #x << ':' << x << ' ' << #y << ':' << y << ' ' << #z << ':' << z << endl
#define     PI              acos(-1)
#define     MP(x, y)        make_pair(x, y)
#define     PB(x)           push_back(x)
#define     ALL(p)          p.begin(),p.end()
#define     CLR(p)          memset(p, 0, sizeof(p))
#define     MEM(a, b)       memset(a, (b), sizeof(a))
#define     ff              first
#define     ss              second
#define     sf              scanf
#define     pf              printf
#define     PII             pair<int, int>
#define     ll              long long int
#define     ull             unsigned long long int

inline int two(int n) { return 1 << n; }
inline int test(int n, int b) { return (n>>b)&1; }
inline void set_bit(int & n, int b) { n |= two(b); }
inline void unset_bit(int & n, int b) { n &= ~two(b); }
inline int last_bit(int n) { return n & (-n); }
inline int ones(int n) { int res = 0; while(n && ++res) n-=n&(-n); return res; }

template < class T > inline T gcd(T a, T b) {while(b) { a %= b; swap(a, b); } return a;}
template < class T > inline T bigmod(T p, T e, T M){
    ll ret = 1;
    for(; e > 0; e >>= 1){ if(e & 1) ret = (ret * p) % M; p = (p * p) % M; }
    return (T)ret;
}
template < class T > inline T power(T a, T n) {
    if(n==0) return 1;
    if(n==1) return a;
    T R = power(a,n/2);
    return (n%2==0) ? R*R : R*a*R;
}

int fx4[] = {0, 0, -1, +1};
int fy4[] = {+1, -1, 0, 0};
int fx8[] = {1, 1, 0, -1, -1, -1, 0, 1, 0};
int fy8[] = {0, 1, 1, 1, 0, -1, -1, -1, 0};
int fx8Knight[] = {+2, +2, +1, -1, -2, -2, -1, +1};
int fy8Knight[] = {+1, -1, -2, -2, -1, +1, +2, +2};


const int MAXN = 107;

map<string, vector<string>> adj;
map<string, bool> vis;
map<string, int> dist;
int N, E;


void bfs(string src)
{
    queue<string> Q;
    Q.push(src);
    vis[src] = true;
    dist[src] = 0;
    while(!Q.empty())
    {
        string king = Q.front();
        Q.pop();
        cout << king << ' ';
        for(auto v : adj[king])
        {
            if(!vis[v])
            {
                vis[v] = true;
                dist[v] = dist[king] + 1;
                Q.push(v);
            }
        }
    }
    cout << "\n\n";
}

int main() {
#ifndef ONLINE_JUDGE
    read;
    write;
#endif
    fast;
    cin >> N >> E;
    for (int i = 0; i < E; i++)
    {
        string u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    bfs("shiary");
    cout << dist["nawreen"] << "\n\n";
    for(auto i : adj)
    {
        cout << i.first << ": ";
        for(auto j : i.second)
        {
            cout << j << ' ';
        }
        cout << endl;
    }
    return 0;
}


//                           key       value
// adj er ekta element, i = {shairy, {ruhan, sajid, abed}}
// i.first = shiary
// i.second.size() = 3;
// i.second[0] = ruhan
// i.second[1] = sajid
// i.second[2] = abed

/*
input:
7 7
shiary ruhan
shiary sajid
ruhan mappy
ruhan anika
anika nawreen
abed shiary
mappy nawreen
output:
shiary ruhan sajid abed mappy anika nawreen

3

abed: shiary
anika: ruhan nawreen
mappy: ruhan nawreen
nawreen: anika mappy
ruhan: shiary mappy anika
sajid: shiary
shiary: ruhan sajid abed
*/