//看看会不会爆int!数组会不会少了一维！

//取物问题一定要小心先手胜利的条件

#include <bits/stdc++.h>

using namespace std;

#pragma comment(linker,"/STACK:102400000,102400000")

#define LL long long

#define ALL(a) a.begin(), a.end()

#define pb push_back

#define mk make_pair

#define fi first

#define se second

#define haha printf("haha\n")

const int maxn = 2e5 + ;

int n, m, k;

vector<int> G[maxn];

bool vis[maxn];

vector<int> ans[maxn];

int lim, cnt, rest;

void dfs(int u){

    vis[u] = true;

    ans[cnt].pb(u); rest--;

    if (rest == ) {cnt++; rest = lim;}

    for (int i = ; i < G[u].size(); i++){

        int v = G[u][i];

        if (vis[v]) continue;

        dfs(v);

        ans[cnt].pb(u); rest--;

        if (rest == ) {cnt++; rest = lim;}

    }

}

int main(){

    cin >> n >> m >> k;

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

        int u, v; scanf("%d%d", &u, &v);

        G[u].pb(v); G[v].pb(u);

    }

    lim = n *  / k;

    if (( * n) % k) lim++;

    rest = lim, cnt = ;

    dfs();

    if (rest == lim) cnt--;

    for (int i = cnt + ; i <= k; i++){

        ans[i].pb(); ans[i].pb(G[][]);

    }

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

        printf("%d ", ans[i].size());

        for (int j = ; j < ans[i].size(); j++){

            printf("%d ", ans[i][j]);

        }

        cout << endl;

    }

    return ;

}