#include <bits/stdc++.h>
#define int long long
using namespace std;

void solve() {
    int n; cin >> n;
    vector<vector<int>> g(n);
    for (int i = 0; i < n - 1; i++) {
        int a, b; cin >> a >> b;
        a--, b--;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    vector<int> sz(n, 0);
    int cent = -1;
    function<void(int, int)> cntsz = [&](int v, int p) {
        sz[v] = 1;
        int is_cent = 1;
        for (int u : g[v]) {
            if (u == p) continue;
            cntsz(u, v);
            if (sz[u] > n / 2) is_cent = 0;
            sz[v] += sz[u];
        }
        if (n - sz[v] > n / 2) is_cent = 0;
        if (is_cent) cent = v;
    };
    cntsz(0, -1);
    fill(sz.begin(), sz.end(), 0);
    bool good = 1;
    function<void(int, int)> dfs = [&](int v, int p) {
        vector<int> sizes;
        sz[v] = 1;
        for (int u : g[v]) {
            if (u == p) continue;
            dfs(u, v);
            sizes.push_back(sz[u]);
            sz[v] += sz[u];
        }
        sort(sizes.begin(), sizes.end());
        int cur = 1;
        for (int s : sizes) {
            if (cur < s) good = 0;
            cur += s;
        }
    };
    dfs(cent, -1);
    if (good) cout << "YES\n";
    else cout << "NO\n";
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    solve();
    return 0;
}