#include <bits/stdc++.h>
#define Nmax 200005

using namespace std;

int n;
set<int> v[Nmax];
set<pair<int,int>> s;
int d[Nmax];
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> n;
    for (int i = 1; i < n; i++)
    {
        int x, y;
        cin >> x >> y;
        v[x].insert(y);
        v[y].insert(x);
    }

    for(int i=1;i<=n;i++)
        d[i] = 1;

    for(int i=1;i<=n;i++)
        if(v[i].size() == 1)
            s.insert(make_pair(d[i], i));

    while(!s.empty())
    {
        auto [nothing, x] = *s.begin();
        s.erase(s.begin());
        if(v[x].size() == 0)
            break;
        auto it = *v[x].begin();
        if(d[x] > d[it])
        {
            cout << "NO";
            return 0;
        }

        v[it].erase(x);
        d[it] += d[x];
        if(v[it].size() == 1)
            s.insert(make_pair(d[it], it));
    }

    cout << "YES";
    return 0;
}