#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long double
#define fi first
#define se second
#define pb push_back
#pragma GCC optimize("unroll-loops,O3")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#define cok cout << (ok ? "YES\n" : "NO\n");
#define dbg(x) cout << (#x) << ": " << x << endl;
#define dbga(x,l,r) cout << (#x) << ": "; for (int ii=l;ii<r;ii++) cout << x[ii] << " "; cout << endl;
#define int long long
#define pi pair<int, int>
const int N = 1e6+9;
pi edge[N];
int a[N], b[N];
vector<int> cmp[N];
bool used[N];
vector<int> vec[N], vecrev[N];
void dfs1(int v, int index) {
    cmp[index].pb(v);
    used[v] = 1;
    for (int i: vec[v]) {
        if (!used[edge[i].se]) dfs1(edge[i].se, index);
    }
    for (int i: vecrev[v]) {
        if (!used[edge[i].fi]) dfs1(edge[i].fi, index);
    }
}
bool uedge[N];
void go(int edge_number, int cmp_number, vector<int> &tek) {
    if (uedge[edge_number]) return;
    uedge[edge_number] = 1;
    tek.pb(edge_number);
    auto [u, v] = edge[edge_number];
    int eu = vec[u][0] == edge_number ? vec[u][1] : vec[u][0];
    int nu = edge[eu].se;
    go(vecrev[nu][0] == eu ? vecrev[nu][1] : vecrev[nu][0], cmp_number, tek);
    int ev = vecrev[v][0] == edge_number ? vecrev[v][1] : vecrev[v][0];
    int nv = edge[ev].fi;
    go(vec[nv][0] == ev ? vec[nv][1] : vec[nv][0], cmp_number, tek);
}
vector<int> bg[N];
int ibg = 0;
vector<pair<int, pi>> global;
void solve(int index) {
    for (int i = 0; i < cmp[index].size(); i++) {
        int vertex = cmp[index][i];
        go(vec[vertex][0], index, bg[ibg]);
        go(vec[vertex][1], index, bg[ibg + 1]);
        int l = -N, r = N;
        for (int edge_number : bg[ibg]) {
            l = max(l, a[edge_number]);
            r = min(r, b[edge_number]);
        }
        global.pb({ibg, {l, r}});
        l = -N, r = N;
        for (int edge_number : bg[ibg + 1]) {
            l = max(l, a[edge_number]);
            r = min(r, b[edge_number]);
        }
        global.pb({ibg + 1, {l, r}});
        ibg += 2;
    }
}
vector<pi> res[N];
int d[N];
void make(int lx, int rx, int v, int l, int r, int x) {
    if (lx >= r || l >= rx) return;
    if (l <= lx && rx <= r) {
        d[v] += x;
        return;
    }
    int m = (lx + rx) / 2;
    make(lx, m, 2 * v + 1, l, r, x);
    make(m, rx, 2 * v + 2, l, r, x);
}
int get(int lx, int rx, int v, int pos) {
    if (rx - lx == 1) return d[v];
    int m = (lx + rx) / 2;
    return d[v] + (pos < m ? get(lx, m, 2 * v + 1, pos) : get(m, rx, 2 * v + 2, pos));
}
signed main()
{
    cin.tie(0);ios_base::sync_with_stdio(0);
    int n;
    cin >> n;
    for (int i = 0; i < 2 * n; i++) {
        int t;
        cin >> t >> a[i] >> b[i];
        t--;
        edge[i] = {i / 2, t};
        vec[i / 2].pb(i);
        vecrev[t].pb(i);
    }
    int index = 0;
    for (int i=0;i<n;i++) {
        if (!used[i]) {
            dfs1(i, index);
            index++;
        }
    }
    for (int i = 0; i < index; i++) {
        solve(i);
    }
    int kol = 1 << 18;
    for (int tk = 0; tk < ibg; tk += 2) {
        auto [l1, r1] = global[tk].se;
        auto [l2, r2] = global[tk + 1].se;
        make(0, kol, 0, l1, r1 + 1, 1);
        make(0, kol, 0, l2, r2 + 1, 1);
        int lint = max(l1, l2);
        int rint = min(r1, r2);
        if (lint <= rint) make(0, kol, 0, lint, rint + 1, -1);
    }
    int nado = ibg >> 1;
    int rs = -1;
    for (int pos = 0; pos < kol; pos++) {
        if (get(0, kol, 0, pos) == nado) {
            rs = pos;
            break;
        }
    }
    if (rs == -1) {
        cout << -1;
        return 0;
    }
    else {
        cout << rs << "\n";
        vector<int> ans;
        for (int tk = 0; tk < ibg; tk += 2) {
            int ind;
            if (global[tk].se.fi <= rs && rs <= global[tk].se.se) {
                ind = global[tk].fi;
            } else {
                ind = global[tk + 1].fi;
            }
            for (int edge_number : bg[ind]) {
                ans.pb(edge_number + 1);
            }
        }
        sort(ans.begin(), ans.end());
        for (int edge_number : ans) cout << edge_number << " ";
    }