data class Node (
    val id: Int,
    var col: Int,
    val ngh: ArrayList<Node> = ArrayList<Node>()

){
    fun colorize(c: Int): Boolean {
//        println("$id -> $c")
        if(col > 0) return col == c
        col = c
        for(x in ngh){
            x.colorize(3 - c)
        }
        return true
    }
}

class Graph(N: Int) {
    val nodes = ArrayList<Node>()

    init {
        for (i in 0 until N) {
            nodes.add(Node(i, 0))
        }
    }

    fun join(a:Int, b:Int){
        nodes[a].ngh.add(nodes[b])
        nodes[b].ngh.add(nodes[a])
    }
}

fun main(args : Array<String>) {

    val N = readLine()!!.toInt()
    val g = Graph(N)
    val seen = HashSet<Int>()
    val leaves = HashSet<Int>()
    for(t in 1 until N) {
        val (a, b) = readLine()!!.split(" ").map { it.toInt() - 1}
        g.join(a, b)
        if(a in seen)leaves.remove(a) else leaves.add(a)
        if(b in seen)leaves.remove(b) else leaves.add(b)
        seen.add(a)
        seen.add(b)
    }

    var ok = true
    for(x in leaves) {
        ok = ok  && g.nodes[x].colorize(1)
    }
    println(if(ok)"Yes" else "No")
}