#include <iostream>
#include <bits/stdc++.h>
using namespace std;
int main() {
    int n;
    cin >> n;
    vector<int> adj[n];
    vector<int> deg(n,0);
    vector<int> count(n,1);
    vector<bool> visited(n,false);
    for(int i = 0; i < n-1; i++){
        int u,v;
        cin >> u >> v;
        u--;
        v--;
        adj[u].push_back(v);
        adj[v].push_back(u);
        deg[u]++;
        deg[v]++;
    }
    queue<int> q;
    for(int i = 0; i < n; i++){
        if(deg[i]==1){q.push(i);}
    }
    bool can = true;
    while(!q.empty()){
        int r = q.size();
        for(int i = 0; i < r; i++){
            int f = q.front();
            q.pop();
            visited[f]=true;
            for(auto e: adj[f]){
                if(!visited[e]){
                    if(count[f]>count[e]){
                        can=false;
                        cout << "NO" << "\n";
                        return 0;
                    }else{
                        count[e]+=count[f];
                        deg[e]--;
                        deg[f]--;
                        if(deg[e]==1){q.push(e);}
                    }
                }
            }
        }

    }
    for(int i = 0; i <n; i++){
        if(deg[i]!=0){can=false; break;}
    }
    if(can){
        cout << "YES" << "\n";
    }else{
        cout << "NO" << "\n";
    }

    return 0;
}