#include <iostream>
#include <algorithm>
#include <vector>
#include <functional>

using namespace std;

// add :: T -> T -> T
//     {v1,v2,...,vm}+vm+1
// bundle :: T -> T
//     u->{v1,v2,v3,...,vm} 
template<class T, class F1, class F2>
vector<T> free_tree_dp(const vector<vector<int>> &g, F1 add, F2 bundle) {
	const int n = g.size();
	vector<T> dp(n);
	function<void(int, int)> dfs = [&](int u, int p) {
		for (int v : g[u]) {
			if (v != p) {
				dfs(v, u);
				dp[u] = add(dp[u], dp[v]);
			}
		}
		dp[u] = bundle(dp[u]);
	};
	dfs(0, -1);
	function<void(int, int)> dfs2 = [&](int u, int p) {
		const int m = g[u].size();
		T l;
		vector<T> r(m);
		for (int i = m - 2; i >= 0; i--) {
			r[i] = add(dp[g[u][i + 1]], r[i + 1]);
		}
		for (int i = 0; i < m; i++) {
			const int v = g[u][i];
			dp[u] = bundle(add(l, r[i]));
			l = add(l, dp[v]);
			if (v != p) {
				dfs2(v, u);
			}
		}
		dp[u] = bundle(l);
	};
	dfs2(0, -1);
	return dp;
}

int main() {
	int n;
	cin >> n;
	vector<vector<int>> g(n);
	for (int i = 0; i < n - 1; i++) {
        int u, v;
        cin >> u >> v;
		u--;
		v--;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	auto add = [&](bool a, bool b) {
        return a || b;
	};
	auto bundle = [&](bool a) {
        return !a;
	};
    auto dp = free_tree_dp<bool>(g, add, bundle);
    cout << count(dp.begin(), dp.end(), true) << endl;
    for (int i = 0; i < n; i++) {
        if (dp[i]) {
            cout << i + 1 << endl;
        }
    }
}