#include <bits/stdc++.h>
using namespace std;
template <typename T>
T Abs(T first) {
  return (first < 0 ? -first : first);
}
template <typename T>
T Sqr(T first) {
  return (first * first);
}
string plural(string s) {
  return (int((s).size()) && s[int((s).size()) - 1] == 'x' ? s + "en"
                                                           : s + "s");
}
const int INF = (int)1e9;
const long double EPS = 1e-9;
const long double PI = acos(-1.0);
bool Read(int &first) {
  char c, r = 0, n = 0;
  first = 0;
  for (;;) {
    c = getchar();
    if ((c < 0) && (!r)) return (0);
    if ((c == '-') && (!r))
      n = 1;
    else if ((c >= '0') && (c <= '9'))
      first = first * 10 + c - '0', r = 1;
    else if (r)
      break;
  }
  if (n) first = -first;
  return (1);
}
int main() {
  if (0) freopen("in.txt", "r", stdin);
  int N;
  int i, j, k, p, pp;
  static int deg[100000], deg2[100000];
  static bool vis[100000];
  static vector<int> con[100000];
  Read(N);
  if (N == 1) goto Yes;
  for (i = 0; i < N - 1; i++) {
    Read(j), Read(k);
    j--, k--;
    deg[j]++;
    deg[k]++;
    con[j].push_back(k);
    con[k].push_back(j);
  }
  for (i = 0; i < N; i++)
    if (deg[i] == 1) {
      vis[i] = 1;
      p = i;
      j = con[i][0];
      while (deg[j] < 3) {
        pp = j;
        vis[j] = 1;
        if (deg[j] == 1) goto Yes;
        if (con[j][0] == p)
          j = con[j][1];
        else
          j = con[j][0];
        p = pp;
      }
      deg2[j]++;
    }
  for (i = 0; i < N; i++)
    if ((deg2[i] == 2) && (deg[i] == 3)) vis[i] = 1;
  for (i = 0; i < N; i++)
    if (!vis[i]) {
      k = 0;
      for (j = 0; j < int((con[i]).size()); j++)
        if (!vis[con[i][j]]) k++;
      if (k > 2) goto No;
    }
Yes:;
  printf("Yes\n");
  return (0);
No:;
  printf("No\n");
  return (0);
}
