// clang-format off
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define mp make_pair
#define fst first
#define snd second
#define forn(i,n) for (int i = 0; i < int(n); i++)
#define forn1(i,n) for (int i = 1; i <= int(n); i++)
#define popcnt __builtin_popcountll
#define ffs __builtin_ffsll
#define ctz __builtin_ctzll
#define clz __builtin_clz
#define clzll __builtin_clzll
#define all(a) (a).begin(), (a).end()

using namespace std;
using namespace __gnu_pbds;

using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;
using pii = pair<int,int>;
using pli = pair<ll,int>;
using pil = pair<int,ll>;
using pll = pair<ll,ll>;
template <typename T> using vec = vector<T>;
using vi = vec<int>;
using vl = vec<ll>;
template <typename T> using que = queue<T>;
template <typename T> using deq = deque<T>;
template <typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template <typename K, typename V> using ordered_map = tree<K, V, less<K>, rb_tree_tag, tree_order_statistics_node_update>;

template <typename T> T id(T b) {return b;};
template <typename T> void chmax(T &x, T y) {if (x < y) x = y;}
template <typename T> void chmin(T &x, T y) {if (x > y) x = y;}
template <typename S, typename K> bool contains(S &s, K k) { return s.find(k) != s.end(); }
template <typename T> bool getf(T flag, size_t i) { return (flag>>i) & 1; }
template <typename T> T setf(T flag, size_t i) { return flag | (T(1)<<i); }
template <typename T> T unsetf(T flag, size_t i) { return flag & ~(T(1)<<i); }
void fastio() { ios_base::sync_with_stdio(false); cin.tie(nullptr); }
constexpr ll TEN(int n) { if (n == 0) return 1LL; else return 10LL*TEN(n-1); }
// clang-format on

namespace aclext {
template <typename S, typename M, typename R, typename C,
    M (*merge)(M, M, int),
    M (*introduce)(M, S, C, int, int),
    M (*em)(),
    R (*result)(M, int),
    S (*subtree)(M, int)>
class Rerooting {
    int n;
    vector<vector<pair<int, C>>> g;
    vector<R> ans;
    vector<vector<S>> dp;

    S dfs1(int u, int p) {
        M s = em();

        int k = g[u].size();

        dp[u] = vector<S>(k);

        for (int i = 0; i < k; i++) {
            auto [v, c] = g[u][i];
            if (v == p) continue;
            dp[u][i] = dfs1(v, u);
            s = introduce(s, dp[u][i], c, u, v);
        }

        return subtree(s, u);
    }

    void dfs2(int u, S par, int p) {
        int k = g[u].size();
        for (int i = 0; i < k; i++) {
            auto [v, c] = g[u][i];
            if (v == p) {
                dp[u][i] = par;
            }
        }

        vector<M> dp_l(k + 1, em()), dp_r(k + 1, em());
        for (int i = 0; i < k; i++) {
            dp_l[i + 1] = introduce(dp_l[i], dp[u][i], g[u][i].second, u, g[u][i].first);
        }
        ans[u] = result(dp_l[k], u);

        for (int i = k - 1; i >= 0; i--) {
            dp_r[i] = introduce(dp_r[i + 1], dp[u][i], g[u][i].second, u, g[u][i].first);
        }

        for (int i = 0; i < k; i++) {
            auto [v, c] = g[u][i];

            if (v == p) continue;

            dfs2(v, subtree(merge(dp_l[i], dp_r[i + 1], u), u), u);
        }
    }

public:
    Rerooting(int n)
        : n(n), g(n), ans(n) { }

    void add_edge(int u, int v, C c = {}) {
        assert(0 <= u && u < n);
        assert(0 <= v && v < n);

        g[u].emplace_back(v, c);
        g[v].emplace_back(u, c);
    }

    vector<R> calc() {
        dp = vector<vector<S>>(n);
        dfs1(0, -1);
        dfs2(0, {}, -1);
        return ans;
    }
};
}

using S = bool;
using M = bool;
using C = bool;
using R = S;

M merge(M a, M b, int) { return a and b; }
M introduce(M a, S b, C c, int, int) { return a and !b; }
M em() { return true; }
R result(M a, int) { return a; }

using rerooting = aclext::Rerooting<S, M, R, C, merge, introduce, em, result, result>;

int main() {
    fastio();

    int n;
    cin >> n;
    rerooting r(n);
    forn(i, n - 1) {
        int u, v;
        cin >> u >> v;
        u--, v--;
        r.add_edge(u, v);
    }

    auto ans = r.calc();

    cout << count(all(ans), true) << "\n";
    forn(i, n) {
        if (ans[i]) {
            cout << (i + 1) << "\n";
        }
    }

    return 0;
}