#include <iostream>
#include <vector>
#include <algorithm>
int main()
{
    std::cin.tie(0);
    std::ios::sync_with_stdio(false);
    int N;
    std::cin >> N;
    std::vector<std::vector<int>> g(N);
    for (int i = 0, a, b; i < N - 1; i++) { std::cin >> a >> b, a--, b--, g[a].push_back(b), g[b].push_back(a); }
    std::vector<bool> win(N);
    std::vector<int> one(N, 0);  // 子供に勝木が何個あるか
    auto dp = [&](auto&& self, const int s, const int p) -> bool {
        for (const int to : g[s]) {
            if (to == p) { continue; }
            one[s] += self(self, to, s);
        }
        return win[s] = one[s] == 0;
    };
    dp(dp, 0, -1);
    std::vector<int> ans;
    auto dp2 = [&](auto&& self, const int s, const int p) -> void {
        if (p == -1) {
            if (win[s]) { ans.push_back(s); }
        } else {
            const int pone = one[p] - win[s];
            win[p] = pone == 0, one[s] += win[p];
            if (one[s] == 0) { ans.push_back(s); }
        }
        for (const int to : g[s]) {
            if (to == p) { continue; }
            self(self, to, s);
        }
    };
    dp2(dp2, 0, -1);
    std::cout << ans.size() << "\n";
    std::sort(ans.begin(), ans.end());
    for (const int e : ans) { std::cout << e + 1 << "\n"; }
    return 0;
}