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

constexpr long long shift = 1LL<<32;

unordered_map<long long, bool> dp;
vector<vector<int>> Es(100000, vector<int>());

bool dfs(int a, int b){
    long long ab = a * shift + b;
    if (dp.count(ab) > 0) return dp[ab];
    for (auto c : Es[b]){
        if (c == a) continue;
        if (not dfs(b, c)){
            dp[ab] = true;
            return true;
        }
    }
    dp[ab] = false;
    return false;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin >> N;
    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);
    }
    for (int a = 0; a < N; ++a){
        for (auto b : Es[a]){
            dfs(a, b);
        }
    }
    vector<int> ans;
    for (int v = 0; v < N; ++v){
        bool v_wins = true;
        for (auto u : Es[v]){
            if (not dp[v * shift + 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;
}