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

// macros
#define pb emplace_back
#define mk make_pair
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define rep(i, n) FOR(i, 0, n)
#define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--)
#define irep(itr, st) for(auto itr = (st).begin(); itr != (st).end(); ++itr)
#define irrep(itr, st) for(auto itr = (st).rbegin(); itr != (st).rend(); ++itr)
#define whole(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define bit(n) (1LL<<(n))
// functions
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;}
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){for(int i = 0; i < vec.size(); i++){ os << vec[i]; if(i + 1 != vec.size())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p){os << "(" << p.first << ", " << p.second << ")"; return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << "(" << itr->first << ", " << itr->second << ")"; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const unordered_map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << "(" << itr->first << ", " << itr->second << ")"; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
//  types
using ll = long long int;
using P = pair<int, int>;
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-10;
const int mod = 1000000007;
const int dx[4] = {-1, 0, 1, 0};
const int dy[4] = {0, -1, 0, 1};
// io
struct fast_io{
  fast_io(){ios_base::sync_with_stdio(false); cin.tie(nullptr); cout << fixed << setprecision(20);}
} fast_io_;

vector<P> edge[100010];
vector<int> res;
int x[100010];
bool used[100010];
void dfs(int i, int p){
  used[i] = true;
  for(auto e: edge[i]){
    if(e.first == p)continue;
    if(used[e.first])continue;
    dfs(e.first, i);
    if(x[e.first] == 1){
      res.pb(e.second + 1);
      x[e.first] = 0;
      x[i] ^= 1;
    }
  }
}

int main(int argc, char const* argv[])
{
  int n, m; cin >> n >> m;
  vector<ll> a_t(n), b_t(n);
  rep(i, n)cin >> a_t[i] >> b_t[i];
  vector<ll> l_t(m), r_t(m);
  rep(i, m)cin >> l_t[i] >> r_t[i];

  vector<int> e(n);
  rep(i, n)e[i] = i;
  sort(whole(e), [&](int i, int j){
    return a_t[i] < a_t[j];
  });
  vector<int> b(n);
  rep(i, n)b[i] = b_t[e[i]];
  vector<ll> a(n);
  rep(i, n)a[i] = a_t[e[i]];
  vector<int> l(m), r(m);
  rep(i, m){
    l[i] = lower_bound(whole(a), l_t[i]) - a.begin();
    r[i] = upper_bound(whole(a), r_t[i]) - a.begin();
    edge[l[i]].pb(r[i], i);
    edge[r[i]].pb(l[i], i);
  }
  x[0] = b[0];
  rep(i, n - 1){
    x[i+1] = b[i] ^ b[i+1];
  }
  x[n] = b[n-1];
  int cnt = 0;
  rep(i, n + 1)cnt += x[i];
  rep(i, n + 1){
    if(!used[i]){
      dfs(i, -1);
      if(x[i] == 1){
        cout << -1 << endl;
        return 0;
      }
    }
  }
  sort(whole(res));
  cout << sz(res) << endl;
  cout << res << endl;
  return 0;
}


Measured memory_bytes: 24444