import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Queue;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] sa = br.readLine().split(" ");
		int n = Integer.parseInt(sa[0]);
		List<List<Integer>> list = new ArrayList<>(n);
		for (int i = 0; i < n; i++) {
			list.add(new ArrayList<>());
		}
		for (int i = 0; i < n - 1; i++) {
			sa = br.readLine().split(" ");
			int a = Integer.parseInt(sa[0]) - 1;
			int b = Integer.parseInt(sa[1]) - 1;
			list.get(a).add(b);
			list.get(b).add(a);
		}
		br.close();

		int c1 = 0;
		int c3 = 0;
		int c = 0;
		for (int i = 0; i < n; i++) {
			if (list.get(i).size() == 1) {
				c1++;
			}
			if (list.get(i).size() > 2) {
				c3++;
				c = i;
			}
		}
		if (c1 == 2 && c3 == 0) {
			System.out.println("Yes");
			return;
		}
		if (c3 > 1) {
			System.out.println("No");
			return;
		}

		int[] d = new int[n];
		Arrays.fill(d, -1);
		d[c] = 0;
		Queue<Integer> que = new ArrayDeque<>();
		que.add(c);
		while (!que.isEmpty()) {
			int cur = que.poll();
			for (int next : list.get(cur)) {
				if (d[next] == -1) {
					que.add(next);
					d[next] = d[cur] + 1;
				}
			}
		}
		int max = 0;
		for (int i = 0; i < n; i++) {
			if (d[i] > max) {
				max = d[i];
			}
		}

		for (int i = 0; i < n; i++) {
			if (list.get(i).size() == 1) {
				if (d[i] != max) {
					System.out.println("No");
					return;
				}
			}
		}
		System.out.println("Yes");
	}
}