#include <bits/stdc++.h>


using namespace std;

const int maxn = 1e6 + 5;
int n , x , y;
vector<pair<int, int>> g[maxn];
vector<pair<int,int>>result;
bool mark[maxn];
int d = 0;

void set_mark_false(int n){
    for (int i = 0; i < n ; i++)
        mark[i] = false;
}

void dfs(int u){
    mark[u] = true;
    for (auto edge : g[u]){
        int v = edge.first;
        int direction = edge.second;
        if (!mark[v] && !direction) d++;
        if (!mark[v]) dfs(v);
    }
}

void check (int u){
    mark[u] = true;
    for (auto w : g[u]){
        int v = w.first;
        int f = w.second;
        if (g[u] == ({v , 1}) && !mark[v]){
            result[v] = make_pair(d+1 , v);
            mark[v] = true;
        } 
        else if (g[u] == ({v , 0}) && !mark[v]) {
            result[v] = make_pair(d , v);
            mark[v] = true;
        }
    }
}

int main(){
    cin >> n;
    result.resize(n);
    for (int i = 0 ; i < n - 1 ; i++){
        cin >> x >> y;
        g[x - 1].push_back({y - 1, 1});
        g[y - 1].push_back({x - 1, 0});
    }
    dfs(0);
    result[0] = make_pair(d , 0);

    sort(result.begin(), result.end());
    cout << result[0].first << endl;
    int min = result[0].first;
    int i = 0;
    bool sw = false;
    while (min == result[i].first){
        if (sw) cout << " ";
        cout << result[i].second + 1;
        sw = true;
        i++;
    }
    cout << endl;  
}