#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main()
{
    int n,m;
    cin>>n>>m;
    int v[n][2];
    for (int i=0;i<n;i++) {
        cin>>v[i][0]>>v[i][1];
    }
    int ap=1,ape,db=0;
    vector<int> von;
    while (ap!=m) {
        ape=ap;
        vector<int> s;
        for (int i=0;i<n;i++) {
            if (ap>=v[i][0] && ap<v[i][1]) s.push_back(v[i][1]);
        }
        sort(s.begin(),s.end());
        ap=s[s.size()-1];
        if(ap==ape) {
            cout<<-1;
            return 0;
        }
        for(int i=0;i<n;i++) {
            if (v[i][1]==ap) {von.push_back(i+1); break;}
        }
        db++;
    }
    cout<<db<<endl;
    for (int i=0;i<db;i++) cout<<von[i]<<" ";
}