#include <iostream>
#include <vector>

using namespace std;

struct A{
     int date, open, fri;

};

int main()
{
    int n, x = 0, f = 0, y = 0;
    cin >> n;
    vector <A> c(n * 2);
    for (int i = 0; i < n * 2; i++){
        cin >> c[x].date;
        c[x].fri = y;
        if(f == 0) {
            c[x].open = 0;
            f++;
        }
        else{
            c[x].open = 1;
            f--;
        }
        x++;
        if(i % 2 != 0 && i != 0) y++;
    }
    x--;
    sort(c.begin(), c.end());
    for (int i = 0; i < x + 1; i++) {
        cout << c[i].date << ' ' << c[i].open << ' ' << c[i].fri << endl;
    }
    vector <pair <int, int> > r(n);
    for(int i = 0; i < x; i++){
        if(c[i - 1].fri == c[i + 2].fri && c[i].fri == c[i + 1].fri){
            r[c[i].fri].first = -1;
            r[c[i].fri].second = -1;
        }
        if(c[i].open == 1 && r[c[i].fri].second == 0){
            r[c[i].fri].second = c[i].date;
        }
        if(c[i].open == 0 && c[i - 1].open == 0 && r[c[i - 1].fri].second == 0){
            r[c[i - 1].fri].second = c[i].date;
        }
        if(c[i].open == 0 && r[c[i].fri].first == 0){
            r[c[i].fri].first = c[i].date;
        }
    }
    for(int i = 0; i < n; i++){
        cout << r[i].first <<  ' ' << r[i].second << endl;
    }
    return 0;
}