#include <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < int(n); i++)
#define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--)
#define reps(i, n) for (int i = 1; i <= int(n); i++)
#define rreps(i, n) for (int i = int(n); i >= 1; i--)
#define repc(i, n) for (int i = 0; i <= int(n); i++)
#define rrepc(i, n) for (int i = int(n); i >= 0; i--)
#define repi(i, a, b) for (int i = int(a); i < int(b); i++)
#define repic(i, a, b) for (int i = int(a); i <= int(b); i++)
#define each(x, y) for (auto &x : y)
#define all(a) (a).begin(), (a).end()
#define bit32(x) (1 << (x))
#define bit64(x) (1ll << (x))

using namespace std;

using i32 = int;
using i64 = long long;
using u64 = unsigned long long;
using f80 = long double;
using vi32 = vector<i32>;
using vi64 = vector<i64>;
using vu64 = vector<u64>;
using vf80 = vector<f80>;
using vstr = vector<string>;

inline void yes() { cout << "Yes" << '\n'; exit(0); }
inline void no() { cout << "No" << '\n'; exit(0); }
inline i64 gcd(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); if (a % b == 0) return b; return gcd(b, a % b); }
inline i64 lcm(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); return a / gcd(a, b) * b; }
inline u64 xorshift() { static u64 x = 88172645463325252ull; x = x ^ (x << 7); return x = x ^ (x >> 9); }
template <typename T> class pqasc : public priority_queue<T, vector<T>, greater<T>> {};
template <typename T> class pqdesc : public priority_queue<T, vector<T>, less<T>> {};
template <typename T> inline void amax(T &x, T y) { if (x < y) x = y; }
template <typename T> inline void amin(T &x, T y) { if (x > y) x = y; }
template <typename T> inline T exp(T x, i64 n, T e = 1) { T r = e; while (n > 0) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; }
template <typename T> inline T bis(T ok, T ng, function<bool(T)> f, T eps = 1) { while (abs(ok - ng) > eps) { T mi = (ok + ng) / 2; (f(mi) ? ok : ng) = mi; } return ok; }
template <typename T> istream& operator>>(istream &is, vector<T> &v) { each(x, v) is >> x; return is; }
template <typename T> ostream& operator<<(ostream &os, vector<T> &v) { rep(i, v.size()) { if (i) os << ' '; os << v[i]; } return os; }
void solve(); int main() { ios::sync_with_stdio(0); cin.tie(0); cout << fixed << setprecision(16); solve(); return 0; }

void solve() {
  int N, M;
  cin >> N >> M;
  vector<pair<int, int>> ve;
  rep(i, N) {
    int a, b;
    cin >> a >> b;
    ve.emplace_back(a, b);
  }
  sort(all(ve));
  vector<pair<int, int>> ranges;
  rep(i, M) {
    int l, r;
    cin >> l >> r;
    int li, ri;
    {
      int ok = N, ng = -1;
      while (ok - ng > 1) {
        int m = (ok + ng) / 2;
        (ve[m].first >= l ? ok : ng) = m;
      }
      li = ok;
    }
    {
      int ok = N, ng = -1;
      while (ok - ng > 1) {
        int m = (ok + ng) / 2;
        (ve[m].first > r ? ok : ng) = m;
      }
      ri = ok;
    }
    ranges.emplace_back(li, ri);
  }
  vi32 val(N + 1);
  int prev = 0;
  rep(i, N) {
    if (prev != ve[i].second) {
      val[i] = 1;
      prev = ve[i].second;
    }
  }
  if (prev == 1) {
    val[N] = 1;
  }
  vector<vector<pair<int, int>>> g(N + 1);
  rep(i, M) {
    int l, r;
    tie(l, r) = ranges[i];
    g[l].emplace_back(r, i + 1);
    g[r].emplace_back(l, i + 1);
  }
  vi32 seen(N + 1);
  vi32 ans;
  auto dfs = [&](auto dfs, int u, int p) -> void {
    seen[u] = 1;
    each(e, g[u]) if (e.first != p) {
      int v, i;
      tie(v, i) = e;
      if (seen[v]) continue;
      dfs(dfs, v, u);
      if (val[v]) {
        val[v] = 0;
        val[u] = 1 - val[u];
        ans.emplace_back(i);
      }
    }
  };
  rep(i, N + 1) {
    if (seen[i]) continue;
    dfs(dfs, i, -1);
    if (val[i]) {
      cout << -1 << endl;
      return;
    }
  }
  sort(all(ans));
  cout << ans.size() << endl;
  cout << ans << endl;
}


Measured memory_bytes: 16240