#include <fstream>
#include <iostream>

using namespace std;

ifstream in ("sortare.in");
ofstream out ("sortare.out");

const int max_size = 5e3 + 1, max_aint = 20e3 + 1;

int a[max_size], b[max_size], c[max_size], p[max_size], ans, nr, n, aint[max_aint];

void init (int l, int r, int nod)
{
    if (l == r)
    {
        aint[nod] = 1;
    }
    else
    {
        int m = (l + r) / 2;
        init(l, m, 2 * nod);
        init(m + 1, r, 2 * nod + 1);
        aint[nod] = aint[2 * nod] + aint[2 * nod + 1];
    }
}

void querry (int l, int r, int poz, int val, int nod)
{
    cout << l << " " << r << '\n';
    if (l == r)
    {
        p[l] = val;
        aint[nod] = 0;
        return;
    }
    int m = (l + r) / 2;
    if (poz <= aint[2 * nod])
    {
        querry(l, m, poz, val, 2 * nod);
    }
    else
    {
        querry(m + 1, r, poz - aint[2 * nod], val, 2 * nod + 1);
    }
    aint[nod] = aint[2 * nod] + aint[2 * nod + 1];
}

void qs (int x)
{
    if (x == 0)
    {
        return;
    }
    ans++;
    if (x == 1)
    {
        querry(1, n, 1, nr, 1);
        return;
    }
    if (a[x] == b[x] || a[x] == c[x] || b[x] == c[x])
    {
        if (a[x] == b[x] || a[x] == c[x])
        {
            querry(1, n, a[x], nr, 1);
        }
        else
        {
            querry(1, n, b[x], nr, 1);
        }
        nr++;
        qs(x - 1);
    }
    else
    {
        querry(1, n, max(a[x], b[x]), nr, 1);
        nr++;
        cout << "*";
        querry(1, n, min(a[x], b[x]), nr, 1);
        nr++;
        qs(x - 2);
    }
}

int main ()
{
    nr = 1;
    in >> n;
    init(1, n, 1);
    for (int i = 2; i <= n; i++)
    {
        in >> a[i] >> b[i] >> c[i];
    }
    qs(n);
    out << ans << '\n';
    for (int i = 1; i <= n; i++)
    {
        out << p[i] << " ";
    }
    in.close();
    out.close();
    return 0;
}