bool isBST(int k,int tree[200000][3], int min, int max){
    if (k==0) return true;
    int lin=tree[k][1];
    int rin=tree[k][2];
    cout << tree[k][0]<<" ";
    if(tree[k][0]<min || tree[k][0]>max) return false;

    return isBST(lin,tree,min,tree[k][0] ) && isBST(rin,tree,tree[k][0],max );
}

bool isBST(int k,int tree[200000][3]){
    return isBST(k,tree, INT_MIN,INT_MAX);

}

int main() {

    ifstream fin("check.in");
    ofstream fout("check.out");
    int n;
    int temp;
    int height = 0;
    fin >> n;
    int tree[200000][3];

    for (int i = 1; i <=n; i++) {
        fin >> temp;
        tree[i][0] = temp;
        fin >> temp;
        tree[i][1] = temp;
        fin >> temp;
        tree[i][2] = temp;
    }
    int h;
    string str;
    if(n>0){
        (isBST(1,tree)) ? str="YES" : str="NO";
        fout << str;
    }
    else fout << "YES";

}