#include <iostream>
#include <algorithm>
#include <vector>
#include <functional>

using namespace std;

bool T[100000];
bool N[100000];
bool ans[100000];

vector<int> g[100000];

void dfs(int u, int p) {
    for (int v : g[u]) if (v != p) {
        dfs(v, u);
        T[u] |= !N[v];
        N[u] |= !T[v];
    }
}

void dfs2(int u, int p) {
    const int m = g[u].size();
    vector<bool> LT(m + 1);
    vector<bool> LN(m + 1);
    vector<bool> RT(m + 1);
    vector<bool> RN(m + 1);
    for (int i = 0; i < m; i++) {
        int v = g[u][i];
        LT[i + 1] = LT[i] || !N[v];
        LN[i + 1] = LN[i] || !T[v];
    }
    for (int i = m - 1; i >= 0; i--) {
        int v = g[u][i];
        RT[i] = RT[i + 1] || !N[v];
        RN[i] = RN[i + 1] || !T[v];
    }
    ans[u] = !LN[m];
    for (int i = 0; i < m; i++) {
        int v = g[u][i];
        if (v == p) continue;
        T[u] = LT[i] || RT[i + 1];
        N[u] = LN[i] || RN[i + 1];
        dfs2(v, u);
    }
}

int main() {
	int n;
	cin >> n;
	for (int i = 0; i < n - 1; i++) {
        int u, v;
        cin >> u >> v;
		u--;
		v--;
		g[u].push_back(v);
		g[v].push_back(u);
	}
    dfs(0, -1);
    dfs2(0, -1);
    cout << count(ans, ans + n, true) << endl;
    for (int i = 0; i < n; i++) {
        if (ans[i]) {
            cout << i + 1 << endl;
        }
    }
}