#include #include using namespace std; using namespace atcoder; typedef long long ll; typedef long double ld; #define REP(i, n) for (int i = 0; i < (n); ++i) #define REPR(i, n) for (int i = n - 1; i >= 0; --i) #define FOR(i, m, n) for (int i = m; i < n; ++i) #define FORR(i, m, n) for (int i = m; i >= n; --i) #define ALL(v) (v).begin(),(v).end() #define ALLR(v) (v).rbegin(),(v).rend() #define fi first #define se second #define PB push_back #define EB emplace_back template using PQ = priority_queue; template using QP = priority_queue,greater>; templatevoid debug(const T &v,ll h,ll w){for(ll i=0;ivoid debug(const T &v,ll n){for(ll i=0;ivoid debug(const vector&v){debug(v,v.size());} templatevoid debug(const vector>&v){for(auto &vv:v)debug(vv,vv.size());} templatevoid debug(stack st){while(!st.empty()){cout<void debug(queue st){while(!st.empty()){cout<void debug(deque st){while(!st.empty()){cout<void debug(PQ st){while(!st.empty()){cout<void debug(QP st){while(!st.empty()){cout<void debug(const set&v){for(auto z:v)cout<void debug(const multiset&v){for(auto z:v)cout<void debug(const array &a){for(auto z:a)cout<void debug(const map&v){for(auto z:v)cout<<"["<bool chmax(T &a, const T &b) { if (abool chmin(T &a, const T &b) { if (b> n; vector> e(n); vector h(n); for (int i = 0; i < n-1; i++){ int a,b;cin >> a >> b; a--,b--; e[a].push_back(b); e[b].push_back(a); h[a]++,h[b]++; } vector d(n); auto dfs=[&](auto &&dfs,int cur,int pre=-1)->void{ for(auto to:e[cur]){ if(to==pre) continue; d[to]=d[cur]+1; dfs(dfs,to,cur); } }; dfs(dfs,0); map mp; FOR(i,1,n) if(h[i]==1) mp[d[i]]++; cout << (mp.size()==1?"Yes":"No") << endl; }