#include <iostream>
using namespace std;
int main()
{
    int emberek[100001]{ 0 };
    int tav[100001]{ 0 };
    int n, max=0,a,b;
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> a >> b;
        emberek[a]++;
        emberek[b+1]--;
        tav[b + 1]++;
        if (b > max)
            max=b;
    }
    for (int i = 2; i <= max; i++) {
        emberek[i] += emberek[i - 1];
    }
    /*for (int i = 1; i <= max; i++) {
        cout << emberek[i] << " ";
    }
    cout << endl;
    for (int i = 1; i <= max; i++) {
        cout << tav[i] << " ";
    }*/
    for (int i = 1; i <= max; i++) {
        if (emberek[i] + tav[i] >= n / 2) {
            cout << "2" << endl;
            cout << i - 1 << " " << i;
            break;
        }
            

        
    }

}