#include<bits/stdc++.h>

using namespace std;

vector<int> p;
vector<vector<int>> adj;

/*
void dfs(int node, int par) {
	p[node] = par;
	for(auto& c : adj[node]) {
		if(c == par) continue;
		dfs(c, node);
	}
}
*/

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);
	int n; cin >> n;
	adj = vector<vector<int>>(n);
	for(int i = 0; i < n - 1; i++) {
		int a,b; cin >> a >> b; a--,b--;
		adj[a].push_back(b);
		adj[b].push_back(a);
	}
	if(n <= 3) {
		cout << "YES" << endl;
		return 0;
	}
	set<pair<int,int>> lvs;
	vector<int> cnt (n, 1);
	vector<int> sz (n);
	for(int i = 0; i < n; i++) {
		sz[i] = adj[i].size();
		if(sz[i] == 1) {
			lvs.insert({cnt[i], i});
		}
	}
	vector<int> vis(n, 0);
	bool bad = 0;
	while((int)lvs.size() > 1) {
		auto [c, node] = *lvs.begin();
		int z;
		for(auto y : adj[node]){
			if(!vis[y]){
				z = y;
				if(cnt[y] < c) {
					bad = 1;
					break;
				}
			}
		}
		if(bad)break;
		vis[node] = 1;
		lvs.erase(lvs.begin());
		cnt[z] += c;
		sz[z]--;
		if(sz[z] == 1) { // Only parent
			lvs.insert({cnt[z], z});
		}
	}
	if(!bad) {
		cout << "YES" << endl;
	} else {
		cout << "NO" << endl;
	}
}