/* -*- coding: utf-8 -*-
 *
 * 1424.cc:  No.1424 Ultrapalindrome - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 100000;

/* typedef */

typedef vector<int> vi;

/* global variables */

vi nbrs[MAX_N];
int ps[MAX_N], ds[MAX_N], cis[MAX_N];

/* subroutines */

/* main */

int main() {
  int n;
  scanf("%d", &n);

  for (int i = 1; i < n; i++) {
    int a, b;
    scanf("%d%d", &a, &b);
    a--, b--;
    nbrs[a].push_back(b);
    nbrs[b].push_back(a);
  }

  int ln = 0, rt = -1;
  for (int u = 0; u < n; u++) {
    int szu = nbrs[u].size();
    if (szu == 1) ln++;
    else if (szu > 2) {
      if (rt < 0) rt = u;
      else { puts("No"); return 0; }
    }
  }
  if (ln == 2) { puts("Yes"); return 0; }

  int ld = -1;
  ps[rt] = -1, ds[rt] = 0;
  for (int u = rt; u >= 0;) {
    vi &nbru = nbrs[u];
    int &ciu = cis[u];
    if (ciu < nbru.size() && nbru[ciu] == ps[u]) ciu++;
    if (ciu < nbru.size()) {
      int v = nbru[ciu++];
      ps[v] = u, ds[v] = ds[u] + 1;
      if (nbrs[v].size() == 1) {
	if (ld < 0) ld = ds[v];
	else if (ld != ds[v]) { puts("No"); return 0; }
      }
      u = v;
    }
    else {
      u = ps[u];
    }
  }

  puts("Yes");
  return 0;
}