//@formatter:off
#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 rep2(i,s,n) for (int i = int(s); i < int(n); ++i)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define pb push_back
#define eb emplace_back
#define vi vector<int>
#define vvi vector<vector<int>>
#define vl vector<ll>
#define vvl vector<vector<ll>>
#define vd vector<double>
#define vvd vector<vector<double>>
#define vs vector<string>
#define vc vector<char>
#define vvc vector<vector<char>>
#define vb vector<bool>
#define vvb vector<vector<bool>>
#define vp vector<P>
#define vvp vector<vector<P>>
using namespace std;
using ll = long long;
using P = pair<int,int>;
using LP = pair<ll,ll>;
template<class S,class T> istream& operator>>(istream &is,pair<S,T> &p) { return is >> p.first >> p.second; }
template<class S,class T> ostream& operator<<(ostream &os,const pair<S,T> &p) { return os<<'{'<<p.first<<","<<p.second<<'}'; }
template<class T> istream& operator>>(istream &is,vector<T> &v) { for(T &t:v){is>>t;} return is; }
template<class T> ostream& operator<<(ostream &os,const vector<T> &v) { os<<'[';rep(i,v.size())os<<v[i]<<(i==int(v.size()-1)?"":","); return os<<']'; }
void Yes(bool b) { cout << (b ? "Yes" : "No") << '\n'; }
void YES(bool b) { cout << (b ? "YES" : "NO") << '\n'; }
template<class T> bool chmin(T& a,T b) {if(a > b){a = b; return true;} return false;}
template<class T> bool chmax(T& a,T b) {if(a < b){a = b; return true;} return false;}
const int inf = 1001001001;
const ll linf = 1001001001001001001;
//@formatter:on

// solve Bx = c  where B is an incidence matrix of a graph
// return void vector if there is no answer
template<class T, bool mod2 = false>
vector<T> incidence_matrix_equation(int n, const vp &edge, const vector<T> &c) {
    assert(c.size() == n);
    
    struct Edge {
        int id, to;
        bool fwd;
        
        Edge(int id, int to, bool fwd) : id(id), to(to), fwd(fwd) {}
    };
    
    vector<vector<Edge>> G(n);
    rep(i, edge.size()) {
        P p = edge[i];
        G[p.first].eb(i, p.second, true);
        G[p.second].eb(i, p.first, false);
    }
    
    vector<T> ans(edge.size());
    vb seen(n);
    
    auto dfs = [&](auto &self, int v) -> T {
        seen[v] = true;
        T res = c[v];
        for (Edge e : G[v]) {
            if (seen[e.to]) continue;
            T d = self(self, e.to);
            if (e.fwd) ans[e.id] = d;
            else ans[e.id] = -d;
            res += d;
            if (mod2) (ans[e.id] += 2) %= 2;
        }
        if (mod2) (res += 2) %= 2;
        return res;
    };
    
    rep(i, n) {
        if (seen[i]) continue;
        T y = dfs(dfs, i);
        if (y != 0) return {};
    }
    
    return ans;
};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int n, m;
    cin >> n >> m;
    vi a(n), b(n);
    rep(i, n) cin >> a[i] >> b[i];
    vi ord(n);
    iota(all(ord), 0);
    sort(all(ord), [&](int i, int j) { return a[i] < a[j]; });
    
    vp v;
    rep(i, m) {
        int l, r;
        cin >> l >> r;
        l = lower_bound(all(ord), l, [&](int val, int key) { return a[val] < key; }) - ord.begin();
        r = lower_bound(all(ord), r + 1, [&](int val, int key) { return a[val] < key; }) - ord.begin();
        v.eb(l, r);
    }
    vi c(n + 1);
    rep(i, n + 1) {
        if (i == 0) c[i] = b[ord[i]];
        else if (i == n) c[i] = b[ord[i - 1]];
        else c[i] = b[ord[i - 1]] ^ b[ord[i]];
    }
    auto ans = incidence_matrix_equation<int, true>(n + 1, v, c);
    if (ans.empty()) {
        cout << -1 << endl;
        return 0;
    }
    vi cut;
    rep(i, m) {
        if (ans[i]) cut.pb(i + 1);
    }
    cout << cut.size() << endl;
    rep(i, cut.size()) {
        cout << cut[i] << (i == cut.size() - 1 ? '\n' : ' ');
    }
}


Measured memory_bytes: 22972