#include <bits/stdc++.h>

using namespace std;

struct node{
    int key;
    int left;
    int right;
};

node a[300001];
int it = 1;

bool check(int ind, int c, int b)
{
  if (ind == NULL)
  {
      return true;
  }
  if (a[ind].key < c || a[ind].key > b)
  {
      return false;
  }
  return check(a[ind].left, c, a[ind].key) && check(a[ind].right, a[ind].key, b);
}

int main()
{
   // ifstream fin("check.in");
    //ofstream fout("check.out");
    int n, si = 0;
    cin >> n;
    if (n == 0)
    {
        cout << "YES";
        return 0;
    }
    for (int i = 1; i <= n; i++)
    {
        cin >> a[i].key >> a[i].left >> a[i].right;
    }
    if (check(1, LONG_MIN, LONG_MAX))
        cout << "YES";
    else
        cout << "NO";
    return 0;
}