#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
//-------------------------------------------------------

int N;
vector<int> E[101010];
map<int,int> memo[101010];

int win(int cur,int pre) {
	if(memo[cur].count(pre)) return memo[cur][pre];
	
	int ng=0;
	FORR(e,E[cur]) if(e!=pre) {
		if(win(e,cur)) {
			ng=1;
			break;
		}
	}
	
	return memo[cur][pre]=ng==0;
}

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>N;
	FOR(i,N-1) {
		cin>>x>>y;
		E[x-1].push_back(y-1);
		E[y-1].push_back(x-1);
	}
	vector<int> R;
	FOR(i,N) if(win(i,-1)) R.push_back(i+1);
	cout<<R.size()<<endl;
	FORR(r,R) cout<<r<<endl;
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}