#include <vector>
#include <iostream>
#include <functional>
using namespace std;
int main() {
	cin.tie(0);
	ios_base::sync_with_stdio(false);
	int N;
	cin >> N;
	vector<vector<int> > G(N);
	for (int i = 0; i < N - 1; ++i) {
		int a, b;
		cin >> a >> b; --a, --b;
		G[a].push_back(b);
		G[b].push_back(a);
	}
	vector<bool> dp_up(N, true), dp_down(N);
	function<void(int, int)> dfs_up = [&](int pos, int pre) {
		int cnt = 0;
		for (int i : G[pos]) {
			if (i == pre) continue;
			dfs_up(i, pos);
			if (dp_up[i]) dp_up[pos] = false;
			++cnt;
		}
	};
	dfs_up(0, -1);
	dp_down[0] = true;
	function<void(int, int)> dfs_down = [&](int pos, int pre) {
		int sum = 0;
		for (int i : G[pos]) {
			if (i == pre) continue;
			sum += (dp_up[i] ? 1 : 0);
		}
		for (int i : G[pos]) {
			if (i == pre) continue;
			if (!dp_down[pos]) dp_down[i] = true;
			if (sum - (dp_up[i] ? 1 : 0) > 0) dp_down[i] = true;
			dfs_down(i, pos);
		}
	};
	dfs_down(0, -1);
	vector<int> ans;
	for (int i = 0; i < N; ++i) {
		if (dp_up[i] && dp_down[i]) {
			ans.push_back(i);
		}
	}
	cout << ans.size() << '\n';
	for (int i : ans) {
		cout << i + 1 << '\n';
	}
	return 0;
}