#include <iostream>
#include <fstream>
#include <set>
#include <cstring>
#include <algorithm>

#if 1
#define pv(x) cout<<#x<<" = "<<x<<"; ";cout.flush()
#define pn cout<<endl
#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;
const int mod = 100003;
using zint = int;

int N,M,Q;
int a[NMax][3],v[NMax];

int solve(int);

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

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

    in.close();out.close();
    return 0;
}

int solve(int dim) {
    if (dim == 0) {
        return 1;
    }
    if (dim == 1) {
        v[1] = 1;
        return 1;
    }

    int ans = 0;
    if (a[dim][0] == a[dim][1] || a[dim][1] == a[dim][2]) {
        ans = solve(dim-1) + 1;

        int idx = a[dim][1], j = dim-1;
        while (idx <= j) {
            v[j+1] = v[j];
            --j;
        }

        v[idx] = dim;
    }
    else {
        ans = solve(dim-2) + 1;

        int idx,j;

        idx = a[dim][0];
        j = dim-2;
        while (idx <= j) {
            v[j+1] = v[j];
            --j;
        }
        v[idx] = dim-1;

        idx = a[dim][1];
        j = dim-1;
        while (idx <= j) {
            v[j+1] = v[j];
            --j;
        }
        v[idx] = dim;
    }

    return ans;
}