#include <bits/stdc++.h>
using namespace std;

bool dfs(int a, int b, vector<unordered_map<int, bool>> & dp, const vector<vector<int>> & Es){
    if (dp[a].count(b) > 0) return dp[a][b];
    for (auto c : Es[b]){
        if (c == a) continue;
        if (not dfs(b, c, dp, Es)){
            dp[a][b] = true;
            return true;
        }
    }
    dp[a][b] = false;
    return false;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin >> N;
    vector<vector<int>> Es(N, vector<int>());
    vector<pair<int, int>> edges;
    for (int i = 1; i < N; ++i){
        int a, b;
        cin >> a >> b;
        Es[a-1].push_back(b-1);
        Es[b-1].push_back(a-1);
        edges.emplace_back(make_pair(a-1, b-1));
        edges.emplace_back(make_pair(b-1, a-1));
    }
    vector<unordered_map<int, bool>> dp(N, unordered_map<int, bool>());
    for (auto &ab : edges){
        dfs(ab.first, ab.second, dp, Es);
    }
    vector<int> ans;
    for (int v = 0; v < N; ++v){
        bool v_wins = true;
        for (auto u : Es[v]){
            if (not dp[v][u]){
                v_wins = false;
                break;
            }
        }
        if (v_wins) ans.push_back(v + 1);
    }
    cout << ans.size() << '\n';
    for (auto v : ans) cout << v << '\n'; 
    return 0;
}