#include <bits/stdc++.h>
using namespace std;
using lint = long long;
const lint mod = 1e9 + 7;
#define all(x) (x).begin(), (x).end()
#define bitcount(n) __builtin_popcountll((lint)(n))
#define fcout cout << fixed << setprecision(15)
#define highest(x) (63 - __builtin_clzll(x))
#define rep(i, n) for(int i = 0; i < n; i++)
const int inf9 = 1e9; const lint inf18 = 1e18;
template<class T> inline void YES(T condition){ if(condition) cout << "YES" << endl; else cout << "NO" << endl; }
template<class T> inline void Yes(T condition){ if(condition) cout << "Yes" << endl; else cout << "No" << endl; }
template<class T = string, class U = char>int character_count(T text, U character){ int ans = 0; for(U i: text){ ans += (i == character); } return ans; }
lint power(lint base, lint exponent, lint module){ if(exponent % 2){ return power(base, exponent - 1, module) * base % module; }else if(exponent){ lint root_ans = power(base, exponent / 2, module); return root_ans * root_ans % module; }else{ return 1; }}
struct position{ double y, x; }; position mv[4] = {{0, -1}, {1, 0}, {0, 1}, {-1, 0}}; double euclidean(position first, position second){ return sqrt((second.x - first.x) * (second.x - first.x) + (second.y - first.y) * (second.y - first.y)); } double euclidean(double first, double second){ return sqrt(first * first + second * second); }
template<class T, class U> string to_string(pair<T, U> x){ return to_string(x.first) + "," + to_string(x.second); } string to_string(string x){ return x; }
template<class itr> void array_output(itr start, itr goal){ string ans; for(auto i = start; i != goal; i++) ans += to_string(*i) + " "; if(!ans.empty()) ans.pop_back(); cout << ans << endl; }
template<class itr> void cins(itr first, itr last){ for(auto i = first; i != last; i++){ cin >> (*i); } }
template<class T> T gcd(T a, T b){ if(a && b){ return gcd(min(a, b), max(a, b) % min(a, b)); }else{ return a; }} template<class T> T lcm(T a, T b){ return a / gcd(a, b) * b; }
struct combination{ vector<lint> fact, inv; combination(int sz) : fact(sz + 1), inv(sz + 1){ fact[0] = 1; for(int i = 1; i <= sz; i++){ fact[i] = fact[i - 1] * i % mod; } inv[sz] = power(fact[sz], mod - 2, mod); for(int i = sz - 1; i >= 0; i--){ inv[i] = inv[i + 1] * (i + 1) % mod; } } lint P(int n, int r){ if(r < 0 || n < r) return 0; return (fact[n] * inv[n - r] % mod); } lint C(int p, int q){ if(q < 0 || p < q) return 0; return (fact[p] * inv[q] % mod * inv[p - q] % mod); } };
template<class itr> bool next_sequence(itr first, itr last, int max_bound){ itr now = last; while(now != first){ now--; (*now)++; if((*now) == max_bound){ (*now) = 0; }else{ return true; } } return false; }
template<class itr, class itr2> bool next_sequence2(itr first, itr last, itr2 first2, itr2 last2){ itr now = last; itr2 now2 = last2; while(now != first){ now--, now2--; (*now)++; if((*now) == (*now2)){ (*now) = 0; }else{ return true; } } return false; }
inline int at(lint i, int j){ return (i >> j) & 1; }

struct UnionFind
{
    vector< int > data;
    
    UnionFind(int sz)
    {
        data.assign(sz, -1);
    }
    
    bool unite(int x, int y)
    {
        x = find(x), y = find(y);
        if(x == y) return(false);
        if(data[x] > data[y]) swap(x, y);
        data[x] += data[y];
        data[y] = x;
        return(true);
    }
    
    int find(int k)
    {
        if(data[k] < 0) return(k);
        return(data[k] = find(data[k]));
    }
    
    int size(int k)
    {
        return(-data[find(k)]);
    }
};

vector<int> diff_global;
vector<vector<pair<int, int>>> roads;
vector<bool> is_came;

vector<int> ans;

int dfs(int now, int back){
    is_came[now] = true;
    int ret = diff_global[now];
    for(auto i: roads[now]){
        if(i.first != back){
            int subtree_dfs = dfs(i.first, now);
            ret += subtree_dfs;
            if(subtree_dfs % 2){
                ans.push_back(i.second + 1);
            }
        }
    }
    return ret;
}

int main(){
    int N, M;
    cin >> N >> M;
    pair<int, int> bomb[N];
    for(int i = 0; i < N; i++){
        int A, B;
        cin >> A >> B;
        bomb[i] = {A, B};
    }
    sort(bomb, bomb + N);
    int A[N], B[N + 2];
    B[0] = B[N + 1] = 0;
    for(int i = 0; i < N; i++){
        A[i] = bomb[i].first;
        B[i + 1] = bomb[i].second;
    }
    int diff[N + 1];
    diff_global.resize(N + 1);
    for(int i = 0; i <= N; i++){
        diff[i] = diff_global[i] = (B[i] ^ B[i + 1]);
    }
    pair<int, int> edges[M];
    for(int i = 0; i < M; i++){
        int L, R;
        cin >> L >> R;
        int l = int(lower_bound(A, A + N, L) - A);
        int r = int(upper_bound(A, A + N, R) - A);
        edges[i] = {l, r};
    }
    roads.resize(N + 1);
    UnionFind uf(N + 1);
    for(int i = 0; i < M; i++){
        int a = edges[i].first, b = edges[i].second;
        //cout << a << " " << b << endl;
        if(uf.find(a) == uf.find(b)){
            continue;
        }
        uf.unite(a, b);
        roads[a].push_back({b, i});
        roads[b].push_back({a, i});
    }
    is_came.resize(N, false);
    for(int i = 0; i < N; i++){
        if(is_came[i]){
            continue;
        }
        int count_1 = dfs(i, -1);
        if(count_1 % 2){
            cout << -1 << endl;
            return 0;
        }
    }
    sort(all(ans));
    cout << ans.size() << endl;
    array_output(all(ans));
}


Measured memory_bytes: 11520