#include <iostream>
#include <vector>
#include <fstream>
using namespace std;

vector < vector < int > > arr;

bool dfs(vector < vector < int > > &arr, int pos, int left, int right)
{
    if (pos < 0)
    {
        return true;
    }
    if (arr[pos][0] >= right || arr[pos][0] <= left)
    {
        return false;
    }

    return (dfs(arr, arr[pos][1], left, arr[pos][0]) && dfs(arr, arr[pos][2], arr[pos][0], right));
}

int main()
{
    ifstream fin("check.in");
    ofstream fout("check.out");

    int n;
    fin >> n;
    arr.resize(n);

    int key, num1, num2;
    if (n == 0)
    {
        fout << "YES";
    } else {
        for (int i = 0; i < n; i++)
        {
            fin >> key >> num1 >> num2;
            arr[i].push_back(key);
            arr[i].push_back(num1 - 1);
            arr[i].push_back(num2 - 1);
        }

        if (dfs(arr, 0, INT32_MIN, INT32_MAX))
        {
            fout << "YES";
        } else {
            fout << "NO";
        }
    }

}