#include <iostream>

 #include <stdio.h>

 #include <vector>

 using namespace std;

 const int MAXN = 2e5 + ;

 vector<int> vt[MAXN];

 int vis[MAXN], path[MAXN << ];

 int indx = ;

 void dfs(int x){

     vis[x] = ;

     path[++indx] = x;

     for(int i = ; i < vt[x].size(); i++){

         if(!vis[vt[x][i]]){

             dfs(vt[x][i]);

             path[++indx] = x;

         }

     }

 }

 int main(void){

     int n, m, k, x, y;

     scanf("%d%d%d", &n, &m, &k);

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

         scanf("%d%d", &x, &y);

         vt[x].push_back(y);

         vt[y].push_back(x);

     }

     dfs();

     int cnt = ( * n + k - ) / k;

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

         int cc = min(cnt, indx);

         if(!cc){

             printf("1 1\n");

             continue;

         }

         printf("%d ", cc);

         for(int j = ; j < cc && indx; j++,indx--){

             printf("%d ", path[indx]);

         }

         puts("");

     }

     return ;

 }