#include <iostream>
#include <cmath>
#include <algorithm>
using namespace std;

struct tree {
    int k, l, r, Lmax, Rmin;
};
int i, n;
tree v[200005];

bool Correct(int j)
{
    if (v[j].k >= v[j].Lmax || v[j].k <= v[j].Rmin) return 0;
    if (v[j].l == 0 and v[j].r == 0) return 1;
    if (v[j].l == 0)
        return Correct(v[j].r);
    if (v[j].r == 0)
        return Correct(v[j].l);
    return (Correct(v[j].l) & Correct(v[j].r));
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    freopen("check.in", "r", stdin);
    freopen("check.out", "w", stdout);
    cin >> n;
    if (n == 0)
    {
        cout << "YES";
        return 0;
    }
    cin >> v[1].k >> v[1].l >> v[1].r;
    v[1].Lmax = 1000000000;
    v[1].Rmin = -1000000000;
    v[v[1].l].Lmax = v[1].k;
    v[v[1].l].Rmin = -1000000000;
    v[v[1].r].Rmin = v[1].k;
    v[v[1].r].Lmax = 1000000000;
    for (i = 2; i <= n; i++)
    {
        cin >> v[i].k >> v[i].l >> v[i].r;
        v[v[i].l].Lmax = v[i].k;
        v[v[i].l].Rmin = v[i].Rmin;

        v[v[i].r].Rmin = v[i].k;
        v[v[i].r].Lmax = v[i].Lmax;
    }

    if (Correct(1))
        cout << "YES";
    else
        cout << "NO";
    return 0;
}