#include <bits/stdc++.h>
using namespace std;
const int inf = ~0U >> 1;
const long long INF = ~0ULL >> 1;
template <class T>
inline void read(T &n) {
  char c;
  for (c = getchar(); !(c >= '0' && c <= '9'); c = getchar())
    ;
  n = c - '0';
  for (c = getchar(); c >= '0' && c <= '9'; c = getchar()) n = n * 10 + c - '0';
}
const int maxn = 200000;
vector<int> E[maxn];
int d[maxn], onPath[maxn], x, y, N;
queue<int> Q;
int main() {
  scanf("%d", &N);
  for (int i = (1); i <= (N - 1); ++i)
    scanf("%d%d", &x, &y), E[x].push_back(y), E[y].push_back(x), d[x]++, d[y]++;
  for (int i = (1); i <= (N); ++i) onPath[i] = 1;
  for (int i = (1); i <= (N); ++i)
    if (d[i] == 1) Q.push(i);
  while (Q.size()) {
    int u = Q.front();
    Q.pop();
    onPath[u] = 0;
    for (auto v : E[u]) {
      --d[v];
      if (d[v] == 1 && E[v].size() <= 2) Q.push(v);
    }
  }
  for (int i = (1); i <= (N); ++i)
    if (onPath[i] && E[i].size() == 3 && d[i] == 1) onPath[i] = 0;
  for (int i = (1); i <= (N); ++i) {
    int cnt = 0;
    for (auto j : E[i])
      if (onPath[j]) ++cnt;
    if (cnt > 2) {
      puts("No");
      return 0;
    }
  }
  puts("Yes");
  return 0;
}
