#include <algorithm>
#include <bitset>
#include <climits>
#include <cmath>
#include <cstdio>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <vector>

#define MOD 1000000007
#define MOD2 998244353
#define int long long
#define EPS 1e-9
//#define PI 3.14159265358979

#define rep(i, n) for (int i = 0; i < (int)(n); i++)

using namespace std;

template < typename T >
ostream &operator<<(ostream &os, const vector< T > &A) {
	for (int i = 0; i < A.size(); i++)
		os << A[i] << " ";
	os << endl;
	return os;
}
template <>
ostream &operator<<(ostream &os, const vector< vector< int > > &A) {
	int N = A.size();
	int M;
	if (N > 0)
		M = A[0].size();
	for (int i = 0; i < N; i++) {
		for (int j = 0; j < M; j++)
			os << A[i][j] << " ";
		os << endl;
	}
	return os;
}

typedef pair< int, int > pii;
typedef long long ll;

struct edge {
	int from, to, d, c;
	edge(int _from = 0, int _to = 0, int _d = 0, int _c = 0) {
		from = _from;
		to = _to;
		d = _d;
		c = _c;
	}
	bool operator<(const edge &rhs) const {
		return (d == rhs.d) ? (c < rhs.c) : (d < rhs.d);
	}
};
struct aabb {
	int x1, y1, x2, y2;
	aabb(int x1, int y1, int x2, int y2) : x1(x1), y1(y1), x2(x2), y2(y2) {}
};

typedef vector< edge > edges;
typedef vector< edges > graph;
struct flow {
	int to, cap, rev, cost;
	flow(int to = 0, int cap = 0, int rev = 0, int cost = 0) : to(to), cap(cap), rev(rev), cost(cost) {}
};
typedef vector< vector< flow > > flows;

const int di[4] = {0, -1, 0, 1};
const int dj[4] = {-1, 0, 1, 0};
const int ci[5] = {0, 0, -1, 0, 1};
const int cj[5] = {0, -1, 0, 1, 0};
const ll LINF = LLONG_MAX / 2;
const int INF = INT_MAX / 2;
const double PI = acos(-1);

int pow2(int n) { return 1LL << n; }
template < typename T, typename U >
bool chmin(T &x, const U &y) {
	if (x > y) {
		x = y;
		return true;
	}
	return false;
}
template < typename T, typename U >
bool chmax(T &x, const U &y) {
	if (x < y) {
		x = y;
		return true;
	}
	return false;
}

struct initializer {
	initializer() {
		cout << fixed << setprecision(20);
	}
};
initializer _____;
struct range {
	int l, r, c;
	range(int l = 0, int r = 0, int c = 0) : l(l), r(r), c(c) {}
	bool operator<(const range &rhs) const {
		return l < rhs.l;
	}
};
int N, M, K, T, Q, H, W;
int dfs1(graph &G, vector< int > &P, vector< int > &done, int x, vector< int > &ans) {
	done[x] = 1;
	int ret = P[x];
	//cout << x << " " << ret << endl;
	for (auto e : G[x]) {
		if (done[e.to])
			continue;
		int tmp = dfs1(G, P, done, e.to, ans);
		if (tmp & 1)
			ans.push_back(e.d);
		ret += tmp;
	}
	//cout << x << " " << ret << endl;
	return ret;
}
signed main() {
	cin >> N >> M;
	vector< pii > B(N);
	rep(i, N) cin >> B[i].first >> B[i].second;
	sort(B.begin(), B.end());
	vector< range > R(M);
	rep(i, M) {
		cin >> R[i].l >> R[i].r;
		R[i].c = i;
	}
	rep(i, M) {
		R[i].l = lower_bound(B.begin(), B.end(), pii(R[i].l, 0)) - B.begin();
		R[i].r = upper_bound(B.begin(), B.end(), pii(R[i].r, 1)) - B.begin();
	}
	//rep(i, M) cout << R[i].l << " " << R[i].r << endl;
	vector< int > ans;
	vector< int > P(N + 1, 0);
	rep(i, N + 1) {
		if (i == 0)
			P[i] = B[i].second;
		else if (i == N)
			P[i] = B[i - 1].second;
		else
			P[i] = B[i].second ^ (B[i - 1].second);
	}
	vector< vector< edge > > G(N + 1);
	rep(i, M) {
		if (R[i].l == R[i].r)
			continue;
		G[R[i].l].push_back(edge(R[i].l, R[i].r, i + 1));
		G[R[i].r].push_back(edge(R[i].r, R[i].l, i + 1));
	}
	vector< int > done(N + 1, 0);
	//cout << P;
	//cout << G;
	rep(i, N + 1) if (!done[i]) {
		if (dfs1(G, P, done, i, ans) & 1) {
			cout << -1 << endl;
			return 0;
		}
	}
	sort(ans.begin(), ans.end());
	cout << ans.size() << endl;
	rep(i, ans.size()) cout << ans[i] << " ";
	cout << endl;
	return 0;
}

Measured memory_bytes: 38012