#include <vector>
#include <iostream>
#include <random>
#include <chrono>
#define rep(i, n) for (int i = 0; i < n; i++)
#define all(x) begin(x), end(x)
#define sz(x) ssize(x)

using namespace std;
using vi = vector<int>;
using vvi = vector<vi>;


int main() {
	cin.tie(0)->sync_with_stdio(0);
	std::mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

	int n, m, k; cin >> n >> m >> k;

	vvi adj(n);
	vi deg(n);
	rep(i, m) {
		int u, v; cin >> u >> v;
		u--, v--;
		adj[u].push_back(v), adj[v].push_back(u);
		deg[u]++, deg[v]++;
	}

	double error = 0.0001;
	int samples = min(3000, static_cast<int>(log(error) / log(1 - pow(4, -k))));
	rep(_, samples) {
		vector<bool> green(n);
		rep(i, n) if (deg[i] <= k) green[i] = rng() % 2;
		vector<bool> vis(n);
		vvi components;
		rep(i, n) if (green[i] && !vis[i]) {
			vector component = {i};
			vis[i] = true;
			rep(j, sz(component))
				for (int v : adj[component[j]]) if (green[v] && !vis[v]) {
					component.push_back(v);
					vis[v] = true;
				}
			components.push_back(component);
		}
		vi edges(sz(components));
		rep(i, sz(components))
			for (int u : components[i])
				for (int v : adj[u])
					edges[i] += !green[v] || (u < v);

		vector dp(sz(components) + 1, vector<char>(k + 1, false));
		dp[0][0] = true;
		rep(i, sz(components))
			rep(j, k + 1) {
			dp[i+1][j] |= dp[i][j];
			if (j + edges[i] <= k)
				dp[i+1][j+edges[i]] |= dp[i][j];
		}
		if (!dp.back().back()) continue;
		vi ans;
		for (int i = sz(components), j = k; i > 0 && j > 0; i--)
			if (dp[i][j] && !dp[i-1][j]) {
				ans.insert(ans.end(), all(components[i-1]));
				j -= edges[i-1];
			}
		cout << sz(ans) << "\n";
		rep(i, sz(ans)) cout << ans[i] + 1 << " \n"[i == sz(ans) - 1];
		return 0;
	}
	cout << "impossible\n";
	return 0;
}