#include <bits/stdc++.h>
using namespace std;
void itval(istream_iterator<string> it) {}
template <typename T, typename... Args>
void itval(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << a << endl;
  itval(++it, args...);
}
const long long int MOD = 1e9 + 7;
template <typename T>
inline void print(T x) {
  cout << x << "\n";
}
template <typename T>
inline void printvec(T x) {
  for (auto a : x) cout << a << ' ';
  cout << '\n';
}
struct custom {
  bool operator()(const pair<int, pair<int, int> > &p1,
                  const pair<int, pair<int, int> > &p2) const {
    if (p1.first == p2.first) return p1.second.first > p2.second.first;
    return p1.first > p2.first;
  }
};
long long int get_pow(long long int a, long long int b, long long int M = MOD) {
  long long int res = 1;
  while (b) {
    if (b & 1) res = (res * a) % M;
    a = (a * a) % M;
    b >>= 1;
  }
  return res;
}
const long long int N = 2e5 + 5, inf = 2e18;
std::vector<int> adj[N];
int comp[N], can, cur, cnt[N];
bool vis[N];
std::vector<int> temp;
void dfs(int s) {
  temp.push_back(s + 1);
  vis[s] = 1;
  cnt[s + 1]++;
  for (auto x : adj[s]) {
    if (!vis[x]) {
      dfs(x);
      temp.push_back(s + 1);
      cnt[s + 1]++;
    }
  }
}
void solve() {
  int n, m, x, y, k;
  cin >> n >> m >> k;
  for (int i = (int)0; i < (int)(m); i++) {
    cin >> x >> y;
    x--;
    y--;
    adj[x].push_back(y);
    adj[y].push_back(x);
  }
  dfs(0);
  while (cnt[temp.back()] > 1) {
    cnt[temp.back()]--;
    temp.pop_back();
  }
  std::vector<int> ans[k];
  int give = temp.size() / k, et = (temp.size()) % k, c = 0;
  for (int i = (int)0; i < (int)(k); i++) {
    for (int j = (int)0; j < (int)(give); j++) ans[i].push_back(temp[c++]);
    if (i < et) ans[i].push_back(temp[c++]);
  }
  for (int i = (int)0; i < (int)(k); i++) {
    cout << ans[i].size() << ' ';
    printvec(ans[i]);
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int test = 1;
  clock_t z = clock();
  for (int tes = (int)0; tes < (int)(test); tes++) {
    solve();
  }
  fprintf(stderr, "Total Time:%.4f\n", (double)(clock() - z) / CLOCKS_PER_SEC),
      fflush(stderr);
  return 0;
}
