#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }
#define COLOR(s) ("\x1b[" s "m")


// !!!Watch out for stack overflow!!!
// Meldable
// 0 for null, ts[0] = T()
// chPoint(u, a, f, args...): point update
// chRange(u, a, b, f, args...): range update s.t. T() -> T()
//   T::push(T *l, T *r)
//   T::pull(const T &l, const T &r)
//   T::meld(const T &t): meld leaf T's

// Manages the number of elements (as a set).
template <class T> struct Seg {
  static constexpr int NUM_NODES = 1 << 23;
  int h;
  int nodesLen;
  int nxt[NUM_NODES][2];
  T ts[NUM_NODES], lz[NUM_NODES];
  void init(int h_) {
    h = h_;
    nodesLen = 1;
    nxt[0][0] = nxt[0][1] = 0;
    ts[0] = T();
    lz[0] = T();
  }
  int newNode() {
    assert(nodesLen < NUM_NODES);
    const int u = nodesLen++;
    nxt[u][0] = nxt[u][1] = 0;
    ts[u] = T(0);
    lz[u] = T(0);
    return u;
  }

  // u: height e
  void ch(int e, int u, T t) {
    if (u) {
      if (e && (t >> (e - 1) & 1)) swap(nxt[u][0], nxt[u][1]);
      lz[u] ^= t;
    }
  }
  void ch(int u, T t) {
    ch(h, u, t);
  }
  // u: height (e+1)
  void push(int e, int u) {
    if (lz[u]) {
      ch(e, nxt[u][0], lz[u]);
      ch(e, nxt[u][1], lz[u]);
      lz[u] = 0;
    }
  }
  void pull(int u) {
    ts[u] = ts[nxt[u][0]] + ts[nxt[u][1]];
  }

  int build(T a) {
    assert(0 <= a); assert(a < T(1) << h);
    const int u = nodesLen;
    for (int e = 0; e <= h; ++e) ts[newNode()] = T(1);
    for (int e = 0; e < h; ++e) nxt[u + (e + 1)][a >> e & 1] = u + e;
    return u + h;
  }

  T mex(int u) {
    if (ts[u] == T(1) << h) return T(1) << h;
    T a = 0;
    for (int e = h; --e >= 0; ) {
      push(e, u);
      if (ts[nxt[u][0]] == T(1) << e) {
        a |= T(1) << e;
        u = nxt[u][1];
      } else {
        u = nxt[u][0];
      }
    }
    return a;
  }

  // Frees v.
  int meld(int e, int u, int v) {
    if (!u) return v;
    if (!v) return u;
    if (!e) {
      ts[u] |= ts[v];
      return u;
    }
    --e;
    push(e, u);
    push(e, v);
    nxt[u][0] = meld(e, nxt[u][0], nxt[v][0]);
    nxt[u][1] = meld(e, nxt[u][1], nxt[v][1]);
    pull(u);
    return u;
  }
  int meld(int u, int v) {
    return meld(h, u, v);
  }

  // Does not push.
  void print(int e, T a, int u) {
    if (!u) return;
    cerr << string(2 * (h - e), ' ') << u << " [" << a << ", " << (a | T(1) << e) << ") " << ts[u] << " " << lz[u] << endl;
    if (!e) return;
    --e;
    print(e, a, nxt[u][0]);
    print(e, a | T(1) << e, nxt[u][1]);
  }
  void print(int u) {
    if (!u) cerr << "[Seg::print] null" << endl;
    print(h, T(0), u);
  }

  // Pushes
  string toString(int e, T a, int u) {
    if (!u) return "";
    if (!e) return to_string(a) + ",";
    --e;
    push(e, u);
    return toString(e, a, nxt[u][0]) + toString(e, a | T(1) << e, nxt[u][1]);
  }
  string toString(int u) {
    return "{" + toString(h, T(0), u) + "}";
  }
};

int N;
vector<int> A, B;

vector<vector<int>> graph;

pair<int, vector<int>> slow(int u, int p) {
  int sum = 0;
  vector<int> xs{0};
  for (const int v : graph[u]) if (p != v) {
    const auto res = slow(v, u);
    sum ^= res.first;
    for (const int x : res.second) xs.push_back(x ^ res.first);
  }
  for (int &x : xs) x ^= sum;
  sort(xs.begin(), xs.end());
  xs.erase(unique(xs.begin(), xs.end()), xs.end());
  for (int x = 0; ; ++x) {
    if (!(x < (int)xs.size() && xs[x] == x)) {
cerr<<"[slow] "<<u<<": "<<x<<" "<<xs<<endl;
      return make_pair(x, xs);
    }
  }
}

vector<int> dp;
Seg<int> seg;
int dfs(int u, int p) {
  int sum = 0;
  int ret = seg.build(0);
  for (const int v : graph[u]) if (p != v) {
    const int res = dfs(v, u);
    sum ^= dp[v];
// cerr<<__LINE__<<": "<<u<<" <- "<<v<<": "<<seg.toString(res)<<endl;//seg.print(ret);
    seg.ch(res, dp[v]);
// cerr<<__LINE__<<": "<<u<<" <- "<<v<<": "<<seg.toString(res)<<endl;//seg.print(ret);
    ret = seg.meld(ret, res);
// cerr<<__LINE__<<": "<<u<<" <- "<<v<<": "<<seg.toString(ret)<<endl;//seg.print(ret);
  }
  seg.ch(ret, sum);
  dp[u] = seg.mex(ret);
// cerr<<"[dfs] "<<u<<": "<<dp[u]<<" "<<seg.toString(ret)<<endl;//seg.print(ret);
  return ret;
}

vector<int> ans;
void DFS(int u, int p, int now) {
  now ^= dp[u];
  for (const int v : graph[u]) if (p != v) now ^= dp[v];
  if (!now) {
    ans.push_back(u);
  }
  for (const int v : graph[u]) if (p != v) {
    DFS(v, u, now);
  }
  now ^= dp[u];
  for (const int v : graph[u]) if (p != v) now ^= dp[v];
}

int main() {
  for (; ~scanf("%d", &N); ) {
    A.resize(N - 1);
    B.resize(N - 1);
    for (int i = 0; i < N - 1; ++i) {
      scanf("%d%d", &A[i], &B[i]);
      --A[i];
      --B[i];
    }
    
    graph.assign(N, {});
    for (int i = 0; i < N - 1; ++i) {
      graph[A[i]].push_back(B[i]);
      graph[B[i]].push_back(A[i]);
    }
    
    int E;
    for (E = 0; !(N < 1 << E); ++E) {}
    seg.init(E);
    dp.assign(N, -1);
    dfs(0, -1);
    
    if (dp[0]) {
      ans.clear();
      DFS(0, -1, dp[0]);
      puts("Alice");
      printf("%d\n", (int)ans.size());
      for (int h = 0; h < (int)ans.size(); ++h) {
        if (h) printf(" ");
        printf("%d", ans[h] + 1);
      }
      puts("");
    } else {
      puts("Bob");
    }
#ifdef LOCAL
slow(0,-1);
#endif
  }
  return 0;
}