#include #define all(v) v.begin(), v.end() #define rall(v) v.rbegin(), v.rend() #define rep(i,n) for (int i=0;i<(int)(n);i++) #define codefor int test;scanf("%d",&test);while(test--) #define INT(...) int __VA_ARGS__;in(__VA_ARGS__) #define LL(...) ll __VA_ARGS__;in(__VA_ARGS__) #define yn(ans) if(ans)printf("Yes\n");else printf("No\n") #define YN(ans) if(ans)printf("YES\n");else printf("NO\n") #define vector1d(type,name,...) vectorname(__VA_ARGS__) #define vector2d(type,name,h,...) vector>name(h,vector(__VA_ARGS__)) #define umap unordered_map #define uset unordered_set using namespace std; using ll = long long; const int MOD=1000000007; //入力系 void scan(int& a){scanf("%d",&a);} void scan(long long& a){scanf("%lld",&a);} template void scan(T& a){cin>>a;} template void scan(vector& vec){for(auto&& it:vec)scan(it);} void in(){} template void in(Head& head, Tail&... tail){scan(head);in(tail...);} //出力系 void print(const int& a){printf("%d",a);} void print(const long long& a){printf("%lld",a);} void print(const double& a){printf("%.15lf",a);} template void print(const T& a){cout< void print(const vector& vec){if(vec.empty())return;print(vec[0]);for(auto it=vec.begin();++it!= vec.end();){putchar(' ');print(*it);}} void out(){putchar('\n');} template void out(const T& t){print(t);putchar('\n');} template void out(const Head& head,const Tail&... tail){print(head);putchar(' ');out(tail...);} //デバッグ系 template void dprint(const T& a){cerr< void dprint(const vector& vec){if(vec.empty())return;cerr< void debug(const T& t){dprint(t);cerr< void debug(const Head& head, const Tail&... tail){dprint(head);cerr<<" ";debug(tail...);} ll intpow(ll a, ll b){ ll ans = 1; while(b){ if(b & 1) ans *= a; a *= a; b /= 2; } return ans; } ll modpow(ll a, ll b, ll p){ ll ans = 1; while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; } ll updivide(ll a,ll b){if(a%b==0) return a/b;else return (a/b)+1;} struct dsu { public: dsu() : _n(0) {} dsu(int n) : _n(n), parent_or_size(n, -1) {} int merge(int a, int b) { assert(0 <= a && a < _n); assert(0 <= b && b < _n); int x = leader(a), y = leader(b); if (x == y) return x; if (-parent_or_size[x] < -parent_or_size[y]) std::swap(x, y); parent_or_size[x] += parent_or_size[y]; parent_or_size[y] = x; return x; } bool same(int a, int b) { assert(0 <= a && a < _n); assert(0 <= b && b < _n); return leader(a) == leader(b); } int leader(int a) { assert(0 <= a && a < _n); if (parent_or_size[a] < 0) return a; return parent_or_size[a] = leader(parent_or_size[a]); } int size(int a) { assert(0 <= a && a < _n); return -parent_or_size[leader(a)]; } std::vector> groups() { std::vector leader_buf(_n), group_size(_n); for (int i = 0; i < _n; i++) { leader_buf[i] = leader(i); group_size[leader_buf[i]]++; } std::vector> result(_n); for (int i = 0; i < _n; i++) { result[i].reserve(group_size[i]); } for (int i = 0; i < _n; i++) { result[leader_buf[i]].push_back(i); } result.erase( std::remove_if(result.begin(), result.end(), [&](const std::vector& v) { return v.empty(); }), result.end()); return result; } private: int _n; // root node: -1 * component size // otherwise: parent std::vector parent_or_size; }; int main(){ INT(n); dsu d(n); vector vec(n,0); int a,b; rep(i,n-1){ in(a,b); d.merge(a,b); vec[a]++; vec[b]++; } vector> G=d.groups(); if(G.size()==1)out("Bob"); else if(G.size()>=3)out("Alice"); else if(G.size()==2){ sort(all(vec)); if(vec[1]<=1)out("Alice"); else out("Bob"); } }