#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <utility>
#include <memory.h>
#include <stack>
#include <queue>
#include <deque>
#include <time.h>
#include <iomanip>
#define pi 3.1415926535897932
#define abs(x) ((x)>0?(x):-(x))
#define sqr(x) ((x)*(x))
#define sci(x) scanf("%d",&x)
#define scd(x) scanf("%lf",&x)
#define pri(x) printf("%d",x)
#define prd(x) printf("%lf",x)
#define inf 0x3f3f3f3f
#define fi first
#define se second
#define tr(container, iterator) for(typeof(container.begin()) iterator=container.begin(); it != container.end(); it++)
#define all(x) x.begin(), x.end()
#define y0 stupid_cmath
#define y1 very_stupid_cmath
#define ll long long
#define pb push_back
#define mp make_pair
#define rep(it,a,b) for(int it=a;it<=b;++it)
#define _rep(it,a,b) for(int it=a;it>=b;--it)
using namespace std;
const int MAXN = 200005;
const int MAXE = 200005;
typedef struct _node
{
int v, w;
int next;
}N;
vector<int> ans;
int Min;
N edge[2 * MAXE];
int cntEdge, head[MAXN];
int dp[MAXN];
void init(int n)
{
Min = 0x7fffffff;
cntEdge = 0;
fill(dp, dp + n + 1, 0);
fill(head, head + n + 1, -1);
}
void addEdge(int u, int v)
{
edge[cntEdge].v = v;
edge[cntEdge].w = 0;
edge[cntEdge].next = head[u];
head[u] = cntEdge++;
edge[cntEdge].v = u;
edge[cntEdge].w = 1;
edge[cntEdge].next = head[v];
head[v] = cntEdge++;
}
void dfs1(int n, int p)
{
for(int f = head[n]; f != -1; f = edge[f].next)
{
if(edge[f].v != p)
{
if(edge[f].w)
dp[1]++;
dfs1(edge[f].v, n);
}
}
}
void dfs2(int n, int p)
{
for(int f = head[n]; f != -1; f = edge[f].next)
{
if(edge[f].v != p)
{
if(edge[f].w == 0)
dp[edge[f].v] = dp[n] + 1;
else
dp[edge[f].v] = dp[n] - 1;
dfs2(edge[f].v, n);
}
}
}
int main()
{
#ifndef ONLINE_JUDGE
freopen("in.txt", "r", stdin);
#endif
int n;
while(scanf("%d", &n) == 1)
{
init(n);
int u, v;
for(int i = 0; i < n - 1; i++)
{
scanf("%d %d", &u, &v);
addEdge(u, v);
}
dfs1(1, 1);
dfs2(1, 1);
rep(i, 1, n)
if(dp[i] < Min)
{
Min = dp[i];
ans.clear();
ans.push_back(i);
}
else if(dp[i] == Min)
{
ans.push_back(i);
}
printf("%d\n", Min);
sort(ans.begin(), ans.end());
rep(i, 0, ans.size() - 1)
{
if(!i)
printf("%d", ans[i]);
else
printf(" %d", ans[i]);
}
puts("");
}
return 0;
}