#include <fstream>

using namespace std;
const int N = 100000;
int L[N], l[N], lung[N+1], val_min[N+1];

ifstream in("drept.in");
ofstream out("drept.out");

void quick_sort(int v[], int st, int dr)
{
	if(st < dr)
	{
		int m = (st + dr) / 2;
		swap(v[st], v[dr]);
		int i = st , j = dr, d = 0;
		while(i < j)
		{
			if(v[i] > v[j])
			{
				swap(v[i], v[j]);
				d = 1 - d;
			}
			i += d;
			j -= 1 - d;
		}
		quick_sort(v, st , i - 1);
		quick_sort(v, i + 1 , dr);
	}
}

int caut_bin(int v[], int n, int x)
{
    int st = 1, dr = n, rez = 0;
    while (st <= dr)
    {
        int m = (st + dr) / 2;
        if (v[m] < x)
        {
            rez = m;
            st = m + 1;
        }
        else
        {
            dr = m - 1;
        }
    }
    return rez;
}

void refac_subsirul(int p, int val, int lg)
{
    if (lg == 1)
    {
        return;
    }
    if (l[p] < val && lung[p] == lg - 1)
    {
        refac_subsirul(p - 1, l[p], lung[p]);
        out << l[p] << " ";
    }
    else
    {
        refac_subsirul(p - 1, val, lg);
    }
}

int main()
{
    int n;
    in >> n;

    for(int i = 0; i < n; i++){
        in >> L[i] >> l[i];
    }

    quick_sort(L, 0, n-1);

    int n_val_min = 0, pmax = 1;

    for (int i = 1; i <= n; i++)
    {
        int j0 = caut_bin(val_min, n_val_min, l[i]);
        if (j0 == n_val_min)
        {
            n_val_min++;
        }
        lung[i] = 1 + j0;
        val_min[lung[i]] = l[i];
        if (lung[i] > lung[pmax])
        {
            pmax = i;
        }
    }
    out << lung[pmax] << "\n";
    refac_subsirul(pmax, l[pmax] + 1, lung[pmax] + 1);

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