#include <bits/stdc++.h>
 
//#include <unistd.h>
//#include <iostream>
 
using namespace std;
 
#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cerr<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl;
#define DEBUG_MAT(v) cerr<<#v<<endl;for(int i=0;i<v.size();i++){for(int j=0;j<v[i].size();j++) {cerr<<v[i][j]<<" ";}cerr<<endl;}
typedef long long ll;
#define int ll
 
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
template<class S, class T> pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first + t.first, s.second + t.second); }
template<class S, class T> pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template<class S, class T> ostream& operator<<(ostream& os, pair<S, T> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
#define X first
#define Y second
#define rep(i,n) for(int i=0;i<(n);i++)
#define rep1(i,n) for(int i=1;i<=(n);i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define rrep1(i,n) for(int i=(n);i>0;i--)
#define REP(i,a,b) for(int i=a;i<b;i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(),c.end()
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; }
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const long double pi = 3.1415926535897932384626433832795028841971L;
#define Sp(p) cout<<setprecision(25)<< fixed<<p<<endl;
//int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
//int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
vi dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};
vi dx2 = { 1,1,0,-1,-1,-1,0,1 }, dy2 = { 0,1,1,1,0,-1,-1,-1 };
#define fio() cin.tie(0); ios::sync_with_stdio(false);
const ll MOD = 1000000007;
//const ll MOD = 998244353;
// #define mp make_pair
//#define endl '\n'



int n, m;
bitset<100010> visited;
bitset<100010> visited2;

vi b2;

vector<vector<pii>> G(100010);
vi op;
vi fin;

int dfs1(int now) {
	visited[now] = true;
	int res = 0;
	if (b2[now]) res++;
	rep (i, G[now].size()) {
		int idx = G[now][i].second;
		int v = G[now][i].first;
		if (v == n) {
			fin.push_back(idx);
			continue;
		}
		if (visited[v]) continue;
		res += dfs1(v);
	}
	return res;
}
	
vector<pll> lr;

void dfs2(int now, int idx) {
	visited2[now] = true;
	rep (i, G[now].size()) {
		int idx2 = G[now][i].second;
		int v = G[now][i].first;
		if (v == n) {
			continue;
		}
		if (visited2[v]) continue;
		dfs2(v, idx2);
	}
	if (b2[now]) {
		op.push_back(idx);
		int l = lr[idx].first, r = lr[idx].second;
		assert(l == now or r == now);
		b2[l] = 1 - b2[l];
		b2[r] = 1 - b2[r];
	}
}

signed main() {
	fio();
	cin >> n >> m;

	vector<pii> ab(n);
	rep (i, n) cin >> ab[i].first >> ab[i].second;
	sort(all(ab));

	vi a(n), b(n);
	rep (i, n) {
		a[i] = ab[i].first;
		b[i] = ab[i].second;
	}
	rep (i, n) {
		if (i == 0) {
			b2.push_back(b[i]);
		}
		else {
			b2.push_back(b[i] != b[i - 1]);
		}
	}

	rep (i, m) {
		int l, r;
		cin >> l >> r;
		int l2 = lower_bound(all(a), l) - a.begin();
		int r2 = upper_bound(all(a), r) - a.begin();
		lr.emplace_back(l2, r2);
		G[l2].push_back(pii(r2, i));
		G[r2].push_back(pii(l2, i));
	}

	rep (i, n) {
		if (visited[i]) continue;
		fin.clear();
		int num = dfs1(i);
		if (num % 2 == 1) {
			if (fin.size() == 0) {
				cout << -1 << endl;
				return 0;
			}
			op.push_back(fin[0]);
			int l = lr[fin[0]].first, r = lr[fin[0]].second;
			assert(r == n);
			b2[l] = 1 - b2[l];
		}

		dfs2(i, -1);
	}

	sort(all(op));
	cout << op.size() << endl;
	rep (i, op.size()) {
		cout << op[i] + 1 << " ";
	}
	cout << endl;
}

Measured memory_bytes: 26476