#pragma GCC optimize("O3")
//#pragma GCC target("avx2")
//#pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<ld> vld;
typedef pair<ll,ll> Pll;
typedef pair<int,int> Pin;

ll INF = 1e16;
int inf = 1e9;

#define ALL(x) (x).begin(), (x).end()
#define FOR(i, m, n) for (ll i = (m); i < (n); ++i)
#define REVFOR(i, m, n) for (ll i = (n - 1); i >= (m); --i)
#define REP(i, n) FOR(i, 0, n)
#define REVREP(i, n) REVFOR(i, 0, n)
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define bcnt __builtin_popcountll

#ifdef LOCAL
#include <prettyprint.hpp>
#define debug(...)  cerr << "[" << #__VA_ARGS__ << "]: ", d_err(__VA_ARGS__);
#else
#define debug(...) 83;
#endif

void d_err() {
    cerr << endl;
}

template <typename H, typename... T>
void d_err(H h, T... t) {
    cerr << h << " ";
    d_err(t...);
}

template <typename T>
void print(T x) {
    cout << x << "\n";
}

template <typename T>
void print(vector<T>& x) {
    int N = x.size();
    REP(i, N) {
        if (i > 0) cout << " ";
        cout << x[i];
    }
    cout << "\n";
}

int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(20);

    int n; cin >> n;
    vector<vi> edge(n);
    REP(i, n - 1) {
        int a, b; cin >> a >> b;
        a--, b--;
        edge[a].eb(b);
        edge[b].eb(a);
    }

    vi dist(n, -1);
    vi split(n);

    auto dfs = [&](auto &&f, int cur, int par = -1, int d = 0, int s = 0) -> void {
        if (edge[cur].size() == 1 && d > 0) {
            dist[cur] = d;
            split[cur] = s;
            return;
        }

        if (edge[cur].size() > 2) s = d;

        for (auto &e: edge[cur]) {
            if (e == par) continue;
            f(f, e, cur, d + 1, s);
        }
    };

    int root;
    REP(i, n) {
        if (edge[i].size() == 1) {
            root = i;
            break;
        }
    }

    dfs(dfs, root);

    int dm = -1;
    int s;
    REP(i, n) {
        if (dist[i] == -1) continue;

        if (dm < 0) {
            dm = dist[i];
            s = split[i];
        } else {
            if (dist[i] != dm || s != split[i]) {
                print("No");
                return 0;
            }
        }
    }

    dist.assign(n, -1);
    dfs(dfs, s);
    dm = -1;

    REP(i, n) {
        if (dist[i] == -1) continue;

        if (dm < 0) {
            dm = dist[i];
        } else {
            if (dist[i] != dm) {
                print("No");
                return 0;
            }
        }
    }

    print("Yes");

}