#include <iostream>
#include <bits/stdc++.h>

using namespace std;
typedef long long int ll;

struct Vertex {
    ll id;
    vector<ll> adj;
    ll deg;
    ll size = 1;
};

vector<Vertex> graph;

bool searchNode(ll id, ll parent) {
    if (graph[id].adj.size() == 1) {
        return true;
    }
    bool pos = true;
    for (int i = 0; i < graph[id].adj.size(); ++i) {
        if (graph[id].adj[i] == parent) continue;
        pos = pos && searchNode(graph[id].adj[i], id);
    }
    if (!pos) return false;
    vector<ll> childSizes;
    for (int i = 0; i < graph[id].adj.size(); ++i) {
        if (graph[id].adj[i] == parent) continue;
        childSizes.emplace_back(graph[graph[id].adj[i]].size);
    }
    sort(childSizes.begin(), childSizes.end());
    for (int i = 0; i < childSizes.size(); ++i) {
        if (childSizes[i] <= graph[id].size) {
            graph[id].size += childSizes[i];
        } else return false;
    }
    return pos;
}

int main() {
    ll n;
    cin >> n;
    graph.resize(n);
    for (int i = 0; i < n - 1; ++i) {
        ll u, v;
        cin >> u >> v;
        u--;
        v--;
        graph[u].adj.emplace_back(v);
        graph[v].adj.emplace_back(u);
    }
    queue<ll> curVtx;
    //vector<bool> visited(n);
    for (int i = 0; i < n; ++i) {

        graph[i].deg = graph[i].adj.size();
        if (graph[i].deg == 1) {
            curVtx.push(i);
            //visited[i] = true;
        }
    }

    ll centroid = -1;
    while (!curVtx.empty()) {
        queue<ll> newQueue;
        while (!curVtx.empty()) {
            ll cur = curVtx.front();
            curVtx.pop();
            centroid = cur;
            for (ll s: graph[cur].adj) {
                graph[s].deg--;
                if (graph[s].deg == 1) {
                    newQueue.push(s);
                }
            }
        }
        curVtx = std::move(newQueue);

        /*for (int i = 0; i < graph[cur].adj.size(); ++i) {
            ll next = graph[cur].adj[i];
            if (!visited[next]) {
                graph[next].size += graph[cur].size;
                graph[next].deg--;
                if (graph[next].deg <= 1 && !visited[next]) {
                    visited[next] = true;
                    curVtx.push(next);
                }
                break;
            }
        }*/
    }
    // cout << centroid << '\n';

    bool pos = searchNode(centroid, -1);
    if (pos) cout << "YES" << endl;
    else cout << "NO" << endl;


    return 0;
}