#include <algorithm>
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <iostream>
#include <numeric>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <functional>
#include <iomanip>
using namespace std;
using ll = long long;

class range {private: struct I{int x;int operator*(){return x;}bool operator!=(I& lhs){return x<lhs.x;}void operator++(){++x;}};I i,n;
public:range(int n_):i({0}),n({n_}){}range(int i_,int n_):i({i_}),n({n_}){}I& begin(){return i;}I& end(){return n;}};

template<typename T, typename U> ostream& operator<<(ostream& os, const pair<T, U>& p){ return os << "{" << p.first << ", " << p.second << "}"; }
template<typename T> ostream& operator<<(ostream& os, const vector<T>& obj) { os << "{"; for (const auto& e : obj) os << e << ", "; return os << "}"; }
template<typename T> ostream& operator<<(ostream& os, const set<T>& obj) { os << "set{"; for (const auto& e : obj) os << e << ", "; return os << "}"; }
template<typename T, typename U> ostream& operator<<(ostream& os, const map<T, U>& obj) { os << "map{"; for (const auto& e : obj) os << e << ", "; return os << "}"; }
template<typename T> void take(vector<T>& vec, int n) { vec.resize(n); for (int i = 0; i < n; ++i) cin >> vec[i]; }

#ifdef ONLINE_JUDGE
#define dump(expr) ;
#else
#define dump(expr) { cerr << "\033[33m#L" << __LINE__ << ": " << expr << "\033[39m" << endl; }
#endif

using EdgeCost = ll;
struct E {
  int fr, to, eid; EdgeCost cost;
  E(int fr_, int to_, int eid_, EdgeCost cost_) : fr(fr_), to(to_), eid(eid_), cost(cost_) {}
  friend ostream &operator<<(ostream &os, const E &e) { os << "(" << e.fr << " -> " << e.to << ")"; return os; }
};
using V = vector<E>;
struct G {
  int n, e_count;
  vector<V> adj, rev;
  G(int n_) : n(n_), e_count(0), adj(n), rev(n) {}

  void add_directed_edge(int fr, int to, EdgeCost cost = (EdgeCost)1) {
    assert(0 <= fr && fr < n); assert(0 <= to && to < n); E e(fr, to, e_count++, cost); adj[fr].push_back(e); rev[to].push_back(e);
  }
  void add_undirected_edge(int fr, int to, EdgeCost cost = (EdgeCost)1) {
    assert(0 <= fr && fr < n); assert(0 <= to && to < n); E e1(fr, to, e_count, cost), e2(to, fr, e_count++, cost);
    adj[fr].push_back(e1); rev[to].push_back(e1); adj[to].push_back(e2); rev[to].push_back(e2);
  }
};

namespace solver {

template<typename T1, typename T2> struct In2 {
  T1 a; T2 b;
  friend std::istream& operator>>(std::istream& is, In2& obj) { T1 t1; T2 t2; is >> t1 >> t2; obj = {t1, t2}; return is; }
};

template<typename T1, typename T2, typename T3> struct In3 {
  T1 a; T2 b; T3 c;
  friend std::istream& operator>>(std::istream& is, In3& obj) { T1 t1; T2 t2; T3 t3; is >> t1 >> t2 >> t3; obj = {t1, t2, t3}; return is; }
};

int n;
vector<In2<int, int>> edges;

void read() {
  cin >> n;
  take(edges, n - 1);
}

using I = pair<int, int>;  // [fir, sec)

void split(I interval, vector<I>& res) {
  auto [a, b] = interval;
  int N = 1 << 20;

  a += N;
  b += N;

  int len = 1;

  auto add = [&](int p) {
    int p2 = p * len;
    res.push_back({p2 - N, p2 + len - N});
  };

  while (a < b) {
    if (a & 1) {
      add(a);
      a++;
    }
    if (b & 1) {
      b--;
      add(b);
    }
    a >>= 1;
    b >>= 1;
    len <<= 1;
  }
}

vector<int> masks;

void take_xor(vector<I>& intervals, int x, vector<I>& res) {
  for (auto interval : intervals) {
    int s = interval.second - interval.first;
    int mask = s - 1;
    int na = (interval.first & ~mask) ^ (x & ~mask);

    res.push_back({na, na + s});
  }
}

vector<I> merge(vector<I>& intervals) {
  vector<I> res;
  int begin = -1, end = -1;
  ranges::sort(intervals);
  for (auto interval : intervals) {
    if (end < interval.first) {
      if (begin >= 0) res.push_back({begin, end});
      begin = interval.first;
      end = interval.second;
    } else {
      end = max(end, interval.second);
    }
  }
  res.push_back({begin, end});
  return res;
}

G g(0);
vector<int> vf, vg;
vector<vector<I>> vGset;

void dfs(int now, int par) {
  for (auto e : g.adj[now]) if (e.to != par) dfs(e.to, now);

  int f = 0;
  for (auto e : g.adj[now]) if (e.to != par) f ^= vg[e.to];
  vf[now] = f;

  vector<I> intervals{{f, f + 1}};

  for (auto e : g.adj[now]) if (e.to != par) {
    take_xor(vGset[e.to], f ^ vg[e.to], intervals);

    if (now == 1) {
      dump(vGset[e.to] << " " << f << " " << vg[e.to])
      dump(intervals)
    }
  }

  intervals = merge(intervals);
  vg[now] = intervals[0].second;

  for (auto interval : intervals) split(interval, vGset[now]);
  dump(now << " " << vGset[now]);


}

vector<int> ans;
void dfs2(int now, int par, int grundy) {
  if (grundy == 0) ans.push_back(now);

  for (auto e : g.adj[now]) if (e.to != par) {
    dfs2(e.to, now, grundy ^ vg[e.to] ^ vf[e.to]);
  }
}

using RetType = void;

RetType run() {
  {
    vector<I> res;
    split({2, 7}, res);
    ranges::sort(res);
    dump(res);
  }
  {
    vector<I> iv{{12, 16}}, res;
    take_xor(iv, 128, res);
    dump(res);
  }

  g = G(n + 1);
  for (auto e : edges) g.add_undirected_edge(e.a, e.b);
  vf.assign(n + 1, -1);
  vg.assign(n + 1, -1);
  vGset.assign(n + 1, vector<I>());

  dfs(1, -1);

  dump(vg);
  dump(vf);

  ans.clear();
  dfs2(1, -1, vf[1]);

  if (ans.size() == 0) {
    cout << "Bob" << endl;
  } else {
    cout << "Alice" << endl;
    cout << ans.size() << endl;
    ranges::sort(ans);
    for (auto a : ans) cout << a << " ";
    cout << endl;
  }
}

}  // namespace

template <typename F>
void run(F f) { if constexpr (std::is_same_v<decltype(f()), void>) f(); else cout << f() << endl; }

int main(int argc, char** argv) {
  cerr << fixed << setprecision(12);
  cout << fixed << setprecision(12);
  int testcase = 1;
  if (argc > 1) testcase = atoi(argv[1]);
  while (testcase--) {
    solver::read();
  }
  run(solver::run);
}