#include <iostream>
#include <vector>
using namespace std;

struct vonat
{
    int start, stop;
};

int main()
{
    int n, m;
    cin >> n >> m;

    vector<vonat> v(n);
    for (int i = 0; i < n; ++i)
    {
        cin >> v[i].start >> v[i].stop;
    }

    int vege = 1,mvege, mindex;
    vector<int> index;
    int i = 0;
    while (vege < m)
    {
        mvege = vege;
        mindex = -1;
        while (i < n && v[i].start <= vege)
        {
            if (v[i].stop > mvege)
            {
                mvege = v[i].stop;
                mindex = i;
            }
            i++;
        }
        if (mindex == -1)
        {
            cout << -1;
            return 0;
        }
        index.push_back(mindex+1);
        vege = mvege;
    }

    cout << index.size() - 1 << endl;
    for (int x : index)
    {
        cout << x << " ";
    }
    return 0;
}