#include <bits/stdc++.h>
using namespace std;
const int N = 1001;
vector<pair<int, int> > g[N];
vector<int> p[N];
vector<pair<pair<int, int>, long long> > ans;
int fa[N], deep[N], hlim[N], a[N], faa[N];
long long co[N][N];
long long lim[N];
int n;
int getfa(int x) { return faa[x] == x ? x : faa[x] = getfa(faa[x]); }
void dfs(int x) {
  deep[x]++;
  if (g[x].size() == 1) {
    p[x].push_back(x);
    lim[x] = hlim[x];
    return;
  }
  for (auto u : g[x])
    if (u.first != fa[x]) {
      fa[u.first] = x;
      hlim[u.first] = u.second;
      deep[u.first] = deep[x];
      dfs(u.first);
    }
}
bool cmp(int x, int y) { return deep[x] > deep[y]; }
void add(int x, int y, long long v) {
  while (v >= 1e9) {
    ans.push_back(make_pair(make_pair(x, y), 1e9));
    v -= 1e9;
  }
  while (v < -1e9) {
    ans.push_back(make_pair(make_pair(x, y), -1e9));
    v += 1e9;
  }
  ans.push_back(make_pair(make_pair(x, y), v));
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i < n; i++) {
    int x, y, z;
    scanf("%d %d %d", &x, &y, &z);
    g[x].push_back(make_pair(y, z));
    g[y].push_back(make_pair(x, z));
  }
  if (n == 2) {
    printf("YES\n");
    printf("1\n");
    printf("1 2 %d\n", g[1][0].second);
    return 0;
  }
  int root = 1;
  while (g[root].size() == 1) root++;
  for (int i = 1; i <= n; i++)
    if (g[i].size() >= 3) {
      root = i;
      break;
    }
  dfs(root);
  for (int i = 1; i <= n; i++) a[i] = i, faa[i] = i;
  sort(a + 1, a + n + 1, cmp);
  for (int i = 1; i <= n; i++) {
    int x = a[i];
    long long all = 0;
    for (auto u : p[x]) all += lim[u];
    if (all != hlim[x] && p[x].size() == 1) {
      printf("NO\n");
      return 0;
    }
    if (abs(all - hlim[x]) & 1) {
      printf("NO\n");
      return 0;
    }
    long long v = (all - hlim[x]) / 2;
    if (v != 0) {
      int y = 0;
      int z = 0;
      while (z < p[x].size() && faa[p[x][z]] == faa[p[x][y]]) z++;
      if (z == p[x].size()) {
        printf("NO\n");
        return 0;
      }
      y = p[x][y];
      z = p[x][z];
      lim[y] -= v;
      lim[z] -= v;
      co[y][z] += v;
    }
    if (x == root) break;
    for (auto u : p[x])
      if (lim[u]) p[fa[x]].push_back(u), faa[u] = x;
  }
  vector<int> d = p[root];
  for (int i = 1; i < d.size(); i++) {
    if (faa[d[i]] != faa[d[0]]) {
      swap(d[1], d[i]);
      break;
    }
  }
  for (int i = 2; i < d.size(); i++)
    if (faa[d[i]] != faa[d[1]]) {
      co[d[1]][d[i]] += lim[d[i]];
      lim[d[1]] -= lim[d[i]];
      lim[d[i]] = 0;
    }
  for (int i = 1; i < d.size(); i++)
    if (faa[d[i]] != faa[d[0]]) {
      co[d[0]][d[i]] += lim[d[i]];
      lim[d[0]] -= lim[d[i]];
      lim[d[i]] = 0;
    }
  if (lim[d[0]]) {
    int z = 0;
    while (z < d.size() && (faa[d[z]] == faa[d[0]] || faa[d[z]] == faa[d[1]]))
      z++;
    if (z == d.size()) {
      printf("NO");
      return 0;
    }
    if (abs(lim[d[0]]) & 1) {
      printf("NO");
      return 0;
    }
    co[d[0]][d[1]] += lim[d[0]] / 2;
    co[d[0]][d[z]] += lim[d[0]] / 2;
    co[d[z]][d[1]] -= lim[d[0]] / 2;
  }
  for (int i = 1; i <= n; i++)
    for (int j = i + 1; j <= n; j++)
      if ((co[i][j] += co[j][i])) {
        add(i, j, co[i][j]);
      }
  printf("YES\n");
  printf("%d\n", ans.size());
  for (auto u : ans) {
    printf("%d %d %lld\n", u.first.first, u.first.second, u.second);
  }
  return 0;
}
