#include "bits/stdc++.h"
using namespace std;
using LL = long long;
using ll = long long;

#define all(x) begin(x),end(x)
typedef array<int, 2> pii;

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	int n; cin >> n;
	vector<set<int>> v(n);
	vector<int> d(n, 1);
	priority_queue<pii, vector<pii>, greater<pii>> q;
	for(int i = 1; i < n; ++i){
		int a, b; cin >> a >> b;
		v[a-1].insert(b-1);
		v[b-1].insert(a-1);
	}
	for(int i = 0; i < n; ++i) if(v[i].size() == 1) q.push({1, i}); // add leaves
	for (int j = 0; j < n - 1; ++j) {
		int i = q.top()[1]; q.pop();
		int p = *v[i].begin();
		if(d[p] < d[i]){ // cannot move leaf, is this a no?
			cout << "NO" << endl;
			exit(0);
		}
		v[p].erase(i);
		d[p] += d[i];
		if(v[p].size() == 1) q.push({d[p], p});
	}
	cout << "YES" << endl;
}
/*
7
5 1
3 2 
4 6
3 6
7 1 1 3

1 2 1 1
3 5 1 1
4 0 1 1
6 0 1 2
5 2 2 2
0 2 3 4
2 0 7 3
NO
*/