#include <bits/stdc++.h>
using namespace std;
vector<int> con[100010];
int dap, cnt2[100010], n, x, y, ch[100010], cnt[100010], sw;
void dfs(int x, int bf) {
  int i;
  for (i = 0; i < con[x].size(); i++) {
    if (bf == con[x][i]) continue;
    cnt[x]++;
    dfs(con[x][i], x);
  }
  if (cnt[x] == 0) ch[x] = 1;
  sw = 0;
  for (i = 0; i < con[x].size(); i++) {
    if (bf == con[x][i]) continue;
    if (cnt[x] == 1 && ch[con[x][i]] == 1) ch[x] = 1;
    if (cnt[x] == 2 && ch[con[x][i]] == 1) sw++;
    if (ch[con[x][i]] != 1) {
      ch[x] = 0;
      return;
    }
  }
  if (cnt[x] == 2 && sw == 2) ch[x] = 2;
  if (cnt[x] >= 3) ch[x] = 0;
}
void dfs2(int x, int bf) {
  int i;
  for (i = 0; i < con[x].size(); i++) {
    if (bf == con[x][i]) continue;
    if (ch[con[x][i]] == 0) cnt2[x]++;
    dfs2(con[x][i], x);
  }
}
void dfs3(int x, int bf, int par) {
  int i, c = 0, p = 0;
  if (x != 1) c++;
  if (par >= 2) {
    if (par >= 3) cnt2[x]++;
    for (i = 0; i < con[x].size(); i++) {
      if (bf == con[x][i]) continue;
      dfs3(con[x][i], x, 3);
    }
    return;
  }
  for (i = 0; i < con[x].size(); i++) {
    if (bf == con[x][i]) continue;
    if (ch[con[x][i]] == 1) c++;
    if (ch[con[x][i]] != 1) {
      if (p) c = 1e9;
      p = i + 1;
    }
  }
  if (c >= 1e9) {
    for (i = 0; i < con[x].size(); i++) {
      if (bf == con[x][i]) continue;
      if (ch[con[x][i]] != 1) dfs3(con[x][i], x, 3);
    }
    return;
  }
  if (p) {
    dfs3(con[x][p - 1], x, c);
    return;
  }
  for (i = 0; i < con[x].size(); i++) {
    if (bf == con[x][i]) continue;
    dfs3(con[x][i], x, c - ch[con[x][i]]);
  }
}
int main() {
  int i;
  scanf("%d", &n);
  for (i = 1; i < n; i++) {
    scanf("%d %d", &x, &y);
    con[x].push_back(y);
    con[y].push_back(x);
  }
  dfs(1, 0);
  dfs2(1, 0);
  dfs3(1, 0, 0);
  for (i = 1; i <= n; i++) {
    if (cnt2[i] >= 3) dap = 1;
  }
  if (dap == 1)
    printf("No");
  else
    printf("Yes");
  return 0;
}
