using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    static int[] LList(long n) => Enumerable.Repeat(0, (int)n).Select(_ => int.Parse(ReadLine())).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var map = NArr(n - 1);
        var tree = new List<int>[n];
        for (var i = 0; i < tree.Length; ++i) tree[i] = new List<int>();
        foreach (var edge in map)
        {
            tree[edge[0] - 1].Add(edge[1] - 1);
            tree[edge[1] - 1].Add(edge[0] - 1);
        }
        var hasBranch = false;
        for (var i = 0; i < n; ++i)
        {
            if (tree[i].Count > 2)
            {
                if (hasBranch)
                {
                    WriteLine("No");
                    return;
                }
                hasBranch = true;
                var dep = new int[n];
                DFS(i, -1, tree, dep);
                var len = -1;
                for (var j = 0; j < n; ++j) if (tree[j].Count == 1)
                {
                    if (len < 0)
                    {
                        len = dep[j];
                    }
                    else if (len != dep[j])
                    {
                        WriteLine("No");
                        return;
                    }
                }
            }
        }
        WriteLine("Yes");
    }
    static void DFS(int cur, int prev, List<int>[] tree, int[] dep)
    {
        foreach (var next in tree[cur])
        {
            if (prev == next) continue;
            dep[next] = dep[cur] + 1;
            DFS(next, cur, tree, dep);
        }
    }
}