#include <iostream>
#include <fstream>
#include <algorithm>

#if 1
#define pv(x) cout<<#x<<" = "<<x<<"; "
#define pn cout<<"\n"
#else
#define pv(x)
#define pn
#endif

using namespace std;
ifstream in("sortare.in");
ofstream out("sortare.out");

using ll = long long;
using ull = unsigned long long;
using ui = unsigned int;
#define pb push_back
#define mp make_pair
const int NMax = 5e3 + 5;
const int inf = 1e9 + 5;
using zint = int;

int N;
int v[NMax],param[NMax][3];

int solve(int);

int main() {
    cin.sync_with_stdio(false);
    cin.tie(0);

    in>>N;
    for (int i=2;i <= N;++i) {
        in>>param[i][0]>>param[i][1]>>param[i][2];
        sort(param[i],param[i]+3);
    }

    int height = solve(N);

    out<<height<<'\n';
    for (int i=1;i <= N;++i) {
        out<<v[i]<<' ';
    }

    return 0;
}

int solve(int nr) {
    if (nr == 1) {
        v[1] = 1;
        return 1;
    }

    if (param[nr][0] == param[nr][1] || param[nr][1] == param[nr][2]) {
        int ret = solve(nr-1) + 1;

        int idx = param[nr][1];
        for (int i=nr;i >= idx;--i) {
            v[i] = v[i-1];
        }
        v[idx] = nr;
        return ret;
    }

    int ret = solve(nr-2) + 1;
    {
        int idx = param[nr][1];

        for (int i=nr;i >= idx;--i) {
            v[i] = v[i-1];
        }
        v[idx] = nr-1;
    }

    {
        int idx = param[nr][2];
        for (int i=nr;i >= idx;--i) {
            v[i] = v[i-1];
        }
        v[idx] = nr;
    }

    return ret;
}