#include <bits/stdc++.h>
using namespace std;

int main() {
    int n, m;
    cin >> n >> m;
    vector<pair<pair<int,int>,int>> v(n);
    for(int i = 0; i < n; i++) {
        cin >> v[i].first.first >> v[i].first.second;
        v[i].second = i+1;
    }
    sort(v.begin(), v.end());

    int pos = 1, max = -1;
    vector<int> ki;
    for(int i = 0; i < n; i++) {
        if(v[i].first.first > pos) {
            if(max == -1) break;

            ki.push_back(v[max].second);
            pos = v[max].first.second;
            max = -1;
        }
        if(v[i].first.first <= pos && (max == -1 || v[i].first.second > v[max].first.second)) max = i;
    }

    if(pos < m) cout << -1;
    else {
        cout << ki.size()-1 << '\n';
        for(auto i : ki) cout << i << ' ';
    }

	return 0;
}