#include <bits/stdc++.h>
using namespace std;
/*#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template<typename T> using gpp_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename L> using gpp_map = tree<T, L, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T> using gpp_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;*/
struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
#define FOR(i, begin, end) for(int i=(begin);i<(end);i++)
#define REP(i, n) FOR(i,0,n)
#define IFOR(i, begin, end) for(int i=(end)-1;i>=(begin);i--)
#define IREP(i, n) IFOR(i,0,n)
#define Sort(v) sort(v.begin(), v.end())
#define Reverse(v) reverse(v.begin(), v.end())
#define all(v) v.begin(),v.end()
#define SZ(v) ((int)v.size())
#define Lower_bound(v, x) distance(v.begin(), lower_bound(v.begin(), v.end(), x))
#define Upper_bound(v, x) distance(v.begin(), upper_bound(v.begin(), v.end(), x))
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
#define bit(n) (1LL<<(n))
#define bit_exist(x, n) ((x >> n) & 1)
#define debug(x) cout << #x << "=" << x << endl;
#define vdebug(v) { cout << #v << "=" << endl; REP(i_debug, v.size()){ cout << v[i_debug] << ","; } cout << endl; }
#define mdebug(m) { cout << #m << "=" << endl; REP(i_debug, m.size()){ REP(j_debug, m[i_debug].size()){ cout << m[i_debug][j_debug] << ","; } cout << endl;} }
#define Return(ans) { cout << (ans) << endl; return 0; }
#define pb push_back
#define f first
#define s second
#define int long long
#define INF 1000000000000000000
template<typename T> istream &operator>>(istream &is, vector<T> &v){ for (auto &x : v) is >> x; return is; }
template<typename T> ostream &operator<<(ostream &os, vector<T> &v){ for(int i = 0; i < v.size(); i++) { cout << v[i]; if(i != v.size() - 1) cout << endl; }; return os; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, pair<T1, T2> p){ cout << '(' << p.first << ',' << p.second << ')'; return os; }
template<typename T> void Out(T x) { cout << x << endl; }
template<typename T1, typename T2> void Ans(bool f, T1 y, T2 n) { if(f) Out(y); else Out(n); }

using vec = vector<int>;
using mat = vector<vec>;
using Pii = pair<int, int>;
using PiP = pair<int, Pii>;
using PPi = pair<Pii, int>;
using bools = vector<bool>;
using pairs = vector<Pii>;

//int dx[4] = {1,0,-1,0};
//int dy[4] = {0,1,0,-1};
//char d[4] = {'D','R','U','L'};

const int mod = 1000000007;
//const int mod = 998244353;
//#define Add(x, y) x = (x + (y)) % mod
//#define Mult(x, y) x = (x * (y)) % mod

struct UnionFind
{
    vector<int> par, sz;
    int n_cc;

    UnionFind(int N){
        par = vector<int>(N);
        REP(i, N) par[i] = i;
        sz = vector<int>(N, 1);
        n_cc = N;
    }

    int find(int x){
        if(par[x] == x) return x;
        else return par[x] = find(par[x]);
    }

    void unite(int x, int y){
        x = find(x);
        y = find(y);
        if(x == y) return;

        if(sz[x] < sz[y]) swap(x, y);

        par[y] = x;
        sz[x] += sz[y];
        n_cc--;
    }

    bool is_union(int x, int y){
        x = find(x);
        y = find(y);
        return x == y;
    }

    int union_size(int x){
        return sz[find(x)];
    }

};

struct edge{int to, cost, id;};

class Graph
{
public:
    int N;
    vector<vector<edge>> G;
    bools used;
    vec c;

    Graph(int N): N(N){
        G = vector<vector<edge>>(N, vector<edge>(0));
        used = bools(N, false);
    }

    void add_Directed_edge(int from, int to, int cost = 1, int id = 0){
        G[from].push_back(edge({to, cost, id}));
    }

    void add_Undirected_edge(int v1, int v2, int cost = 1, int id = 0){
        add_Directed_edge(v1, v2, cost, id);
        add_Directed_edge(v2, v1, cost, id);
    }

    int dfs(int v, vec &ans, int p = -1){
        int cnt = 0;
        for(auto e: G[v]) if(e.to != p){
            int tmp = dfs(e.to, ans, v);
            if(tmp % 2) ans.pb(e.id);
            cnt += tmp;
        }
        if(c[v]) cnt++;
        return cnt;
    }

    
};


signed main(){

    int N, M; cin >> N >> M;
    vec A(N), B(N);
    vec v({-INF, INF});
    REP(i, N){
        cin >> A[i] >> B[i];
        v.pb(A[i]);
    }
    Sort(v);

    vec b(N + 2), c(N + 1);
    REP(i, N){
        int i0 = Lower_bound(v, A[i]);
        b[i0] = B[i];
    }
    REP(i, N + 1) c[i] = b[i] ^ b[i + 1];

    vec L(M), R(M), l(M), r(M);
    UnionFind UF(N + 1);
    Graph G(N + 1);
    REP(i, M){
        cin >> L[i] >> R[i];
        int x = Lower_bound(v, L[i]) - 1, y = Upper_bound(v, R[i]) - 1;
        if(!UF.is_union(x, y)){
            UF.unite(x, y);
            G.add_Undirected_edge(x, y, 0, i);
        }
    }
    G.c = c;

    vec ans;
    REP(i, N) if(UF.find(i) == i) G.dfs(i, ans);

    vec sz(N + 1, 0);
    REP(i, N + 1) if(c[i]) sz[UF.find(i)]++;

    REP(i, N + 1){
        if(sz[i] % 2){
            Return(-1);
        }
    }

    Sort(ans);
    Out(SZ(ans));
    for(int x: ans) cout << x + 1 << ' ';
    cout << endl;

    return 0;
}


Measured memory_bytes: 23924