4
1 4
3 1
3 4
 5
4 1
4 3
5 3
2 4
 21
7 15
13 1
14 3
4 10
2 3
16 18
17 20
16 20
8 4
3 12
2 17
13 11
16 1
13 2
13 5
8 9
6 14
3 17
16 9
13 8
 3
3 1
3 2
 6
5 2
5 3
1 4
3 1
5 6
 60
17 34
46 22
50 44
46 33
41 21
31 33
48 6
38 19
35 60
2 24
49 29
7 53
34 1
19 55
32 1
31 42
27 28
4 53
6 50
21 34
1 10
12 36
54 8
16 13
51 43
45 51
54 20
13 53
34 33
49 33
51 11
59 34
15 5
59 28
30 39
13 30
58 4
34 14
3 9
19 34
4 18
26 48
56 54
3 43
57 25
3 41
35 3
48 44
19 13
54 1
23 31
59 47
5 1
46 40
6 26
20 25
37 5
17 24
20 52
 3
3 2
1 2
 39
6 13
15 39
10 35
31 28
4 21
12 39
3 7
3 13
6 1
5 14
36 28
12 15
18 38
30 29
19 34
36 16
20 22
8 13
38 32
26 39
21 37
1 7
15 27
12 26
8 3
6 14
29 2
25 23
32 21
5 16
32 25
6 8
13 10
23 30
34 37
29 33
28 14
36 5
 10
5 9
8 5
7 6
7 9
3 9
2 1
7 2
3 6
7 1

1
3 4 1 2  0
 3
13 2 1 7 3 17 1 19 13 8 1 21  0
 0
 2
48 44 1 6 6 26 1 12  0
 7
12 15 1 2 1 7 1 9 12 26 1 11 8 3 1 12 6 8 1 17 28 14 1 20 36 5 1 24  2
3 6 1 4 7 1 1 10 
/*
*   Abhishek Soni.....[3rd Year Undergraduate at NSUT]
*   [Email::abhishekk201202@gmail.com]
*   [Codeforces::abhishekk201202]
*   [Codechef::abhishek201202]
*/
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;

template<class T1, class T2> ostream &operator<<(ostream &os, const pair<T1,T2> &p){ os << '{' << p.first << ", " << p.second << '}'; return os;}
template<typename C,typename T = decay_t<decltype(*begin(declval<C>()))>,typename enable_if<!is_same<C,string>::value>::type* = nullptr>
ostream &operator<<(ostream &os, const C &container){bool first = true; stringstream ss; ss << '[';for(const auto &x : container){ if(!first) ss << ", "; first = false; ss << x;} ss << ']';return os << ss.str();}
vector<string> split(const string& s, char c){ vector<string> v; stringstream ss(s); string x; while (getline(ss, x, c)) v.emplace_back(x); return v;}
inline void dbg_out(vector<string>::iterator it){ cerr << endl; }
template<typename T, typename... Args> inline void dbg_out(vector<string>::iterator it, T a, Args... args){ cerr << "[" << it->substr((*it)[0] == ' ', it->length()) << " = " << a << "] "; dbg_out(++it, args...); }
#define debugg(...) {cerr << "[Line " << __LINE__ << "] :: "; dbg_out(split(#__VA_ARGS__, ',').begin(), __VA_ARGS__);}

#define endl             "\n"
#define ff               first
#define ss               second
#define int              long long
#define dd               long double
#define pb               push_back
#define ALL(x)           x.begin(), x.end()
#define FOR(i, s, e)     for(int i = s; i <= e; i++)
#define FORR(i, s, e)    for(int i = s; i >= e; i--)
typedef pair<int, int>   pii;
typedef pair<int, pii>   piii;

template<typename T> using pbds = tree<T, null_type, less<T>, 
rb_tree_tag ,tree_order_statistics_node_update>; 

const int mod = 1e9 + 7;
const int MOD = 998244353;
const int N   = 5e5 + 5;


void test_cases(){
    int n; cin >> n;
    vector<array<int, 2>> a(n - 1);
    for(int i = 0; i < n - 1; i++){
        cin >> a[i][0] >> a[i][1];
    }
    vector<int> par(n);
    iota(ALL(par), 0);

    function<int(int)> get_par = [&](int u){
        if(par[u] == u) return u;
        return par[u] = get_par(par[u]);
    };

    array<int, 2> cycle = {-1ll, -1ll};
    for(int i = 0; i < n - 1; i++){
        auto [x, y] = a[i];
        x--, y--;
        int px = get_par(x);
        int py = get_par(y);
        if(px != py){
            par[px] = py;
        }else{
            cycle = {x, y};
            break;
        }
    }
    if(cycle[0] == -1 && cycle[1] == -1){
        cout << 0 << endl;
        return;
    }
    set<int> cx;
    for(int i = 0; i < n - 1; i++){
        if(a[i][0] == cycle[0] || a[i][1] == cycle[0]){
            cx.insert(a[i][0]);
            cx.insert(a[i][1]);
        }
    }
    cout << 1 << endl;
    cout << cycle[0] + 1 << " " << cycle[1] + 1 << " " << cycle[0] + 1 << " ";
    for(int i = 0; i < n; i++){
        if(cx.find(i) == cx.end() && i != cycle[1]){
            cout << i + 1 << endl;
            return;
        }
    }

    

}


int32_t main(){
    ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
    int tt = 1;
    // cin >> tt;
    for(int T = 1; T <= tt; T++){
        cerr << endl << "Case #" << T << ": " << endl;
        test_cases();
    }
}