#include <iomanip>
#include <iostream>
#include <map>
#include <set>
#include <vector>
#define f(i, s, k, l) for (int i = s; i < k; i += l)
#define for0(i, k) f(i, 0, k, 1)

#define pl pair<long long, long long>
#define pb push_back
#define vl vector<long long>
#define vi vector<int>
#define sz(x) (ll)(x).size()

using namespace std;
using ll = long long;
using ld = long double;

struct edge {
    ll to;
    ld l, v, newv;
};

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    ll n, m, k, a, b;
    cin >> n >> m >> k;

    vector<map<ll, ll>> adj(n);
    vl deg(n);
    for0(i, m) {
        cin >> a >> b;
        a--; b--;
        adj[a][b]++; adj[b][a]++;
        deg[a]++; deg[b]++;
    }
    vl choose;
    for0(i, n) {
        if (deg[i] == k) {
            cout << 1 << endl << i + 1 << endl;
            return 0;
        }
        if (deg[i] <= k && deg[i] != 0) choose.pb(i);
    }
    for (ll i = 1; i < 1 << min(sz(choose), 20ll); i++) {
        if (__builtin_popcount(i) < 2 || __builtin_popcount(i) > 12) continue;
        set<ll> check;
        for (ll j = 0; j < 20; j++) {
            if ((i >> j) & 1) {
                if (j < sz(choose)) check.insert(choose[j]);
            }
        }
        ll inside = 0;
        ll total = 0;
        for (ll x : check) {
            for (pl neigh : adj[x]) {
                if (check.find(neigh.first) != check.end()) inside += neigh.second;
                else total += neigh.second;
            }
            if (total > k) break;
        }
        if (total + inside / 2 == k) {
            cout << sz(check) << endl;
            for (ll x : check)  cout << x + 1 << " ";
            cout << endl;
            return 0;
        }
    }
    cout << "impossible" << endl;

}