#include <bits/stdc++.h>
using namespace std;
using lint = long long int;
using pint = pair<int, int>;
using plint = pair<lint, lint>;
struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((lint)(x).size())
#define POW2(n) (1LL << (n))
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
template<typename T> istream &operator>>(istream &is, vector<T> &vec){ for (auto &v : vec) is >> v; return is; }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &vec){ os << "["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const deque<T> &vec){ os << "deq["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &pa){ os << "(" << pa.first << "," << pa.second << ")"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const unordered_map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
template<typename T> void ndarray(vector<T> &vec, int len) { vec.resize(len); }
template<typename T, typename... Args> void ndarray(vector<T> &vec, int len, Args... args) { vec.resize(len); for (auto &v : vec) ndarray(v, args...); }
template<typename T> bool mmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; }
template<typename T> bool mmin(T &m, const T q) { if (q < m) {m = q; return true;} else return false; }
template<typename T1, typename T2> pair<T1, T2> operator+(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first + r.first, l.second + r.second); }
template<typename T1, typename T2> pair<T1, T2> operator-(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first - r.first, l.second - r.second); }
#define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl;


// UnionFind Tree (0-indexed), based on size of each disjoint set
struct UnionFind
{
    std::vector<int> par, cou;
    UnionFind(int N = 0) : par(N), cou(N, 1) {
        iota(par.begin(), par.end(), 0);
    }
    int find(int x) { return (par[x] == x) ? x : (par[x] = find(par[x])); }
    bool unite(int x, int y) {
        x = find(x), y = find(y);
        if (x == y) return false;
        if (cou[x] < cou[y]) std::swap(x, y);
        par[y] = x, cou[x] += cou[y];
        return true;
    }
    int count(int x) { return cou[find(x)]; }
    bool same(int x, int y) { return find(x) == find(y); }
};

int main()
{
    int N, M;
    cin >> N >> M;

    map<int, int> pos2color;
    pos2color[-1] = 0, pos2color[1.2e9] = 0;
    while (N--) {
        int a, b;
        cin >> a >> b;
        pos2color[a] = b;
    }
    vector<int> x;
    vector<int> color;
    for (auto p : pos2color) x.push_back(p.first), color.push_back(p.second);
    IFOR(i, 1, color.size()) color[i] ^= color[i - 1];

    vector<pint> edges(M);
    REP(i, M) {
        int l, r;
        cin >> l >> r;
        int a = lower_bound(x.begin(), x.end(), l) - x.begin();
        int b = upper_bound(x.begin(), x.end(), r) - x.begin();
        edges[i] = pint(a, b);
    }
    UnionFind uf(x.size());
    vector<set<int>> to(x.size());
    REP(i, M) {
        int a = edges[i].first, b = edges[i].second;
        if (uf.same(a, b)) continue;
        uf.unite(a, b);
        to[a].insert(i);
        to[b].insert(i);
    }

    vector<int> ret;
    queue<int> leaf;

    REP(i, to.size()) if (to[i].size() == 1) leaf.push(i);

    while (!leaf.empty()) {
        int now = leaf.front();
        leaf.pop();
        if (to[now].empty()) continue;
        int eid = *to[now].begin();
        to[now].clear();
        int nxt = edges[eid].first + edges[eid].second - now;
        if (color[now]) color[nxt] ^= 1, color[now] ^= 1, ret.push_back(eid);
        to[nxt].erase(eid);
        if (to[nxt].size() == 1) leaf.push(nxt);
    }

    for (auto d : color) if (d) {
        puts("-1");
        return 0;
    }

    sort(ret.begin(), ret.end());
    cout << ret.size() << "\n";
    for (auto x : ret) cout << x + 1 << " ";
    cout << "\n";
}


Measured memory_bytes: 22772