//c++ -std=gnu++14 a.cpp
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <iostream>
#include <istream>
#include <iterator>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
#include <tuple>
#include <iomanip>
#include <climits>
#include <fstream>
#include <random>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
//typedef pair<ll, ll> P;
#define rep(i, n) for(int i = 0; i < (n); i++)
#define revrep(i, n) for(int i = (n)-1; i >= 0; i--)
#define pb push_back
#define f first
#define s second
#define chmin(x, y) x = min(x, y);
#define chmax(x, y) x = max(x, y);
#define sz(x) ((int)(x).size())

//const ll INFL = LLONG_MAX;//10^18 = 2^60
const ll INFL = 1LL<<60;
//const int INF = INT_MAX;
const int INF = 1 << 30;//10^9
//const int MOD = 1000000007;
const int MOD = 998244353;
//int MOD = 1000000007;
double EPS = 1e-10;

vector<ll> dy = {0, 1, 0, -1, 1, 1, -1, -1, 0};
vector<ll> dx = {1, 0, -1, 0, 1, -1, 1, -1, 0};

void pres(double A){printf("%.12lf\n", A);}
void BinarySay(ll x, ll y = 60){rep(i, y) cout << (x>>(y-1-i) & 1); cout << endl;}
ll cnt_bit(ll x){return __builtin_popcountll(x);}

ll pow_long(ll x, ll k){
  ll res = 1;
  while(k > 0){
    if(k % 2) res *= x;
    x *= x; k /= 2;
  }
  return res;
}

ll pow_mod(ll x, ll k){
  x %= MOD;
  ll res = 1;
  while(k > 0){
    if(k % 2){
      res *= x; res %= MOD;
    }
    x *= x; x %= MOD;
    k /= 2;
  }
  return res;
}

ll inverse(ll x){return pow_mod(x, MOD - 2);};

ll gcd(ll a, ll b){
    if(b == 0) return a;
    return gcd(b, a % b);
}

ll lcm(ll x, ll y){
  ll res = x / gcd(x, y);
  res *= y;
  return res;
};


//コンビネーション
const int MAXcomb = 200010;
ll fac[MAXcomb], finv[MAXcomb], inv[MAXcomb];
//facはn!,finvは1/n!
//invは逆元
void COMinit(){
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for(int i = 2; i < MAXcomb; i++){
        fac[i] = fac[i-1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD/i) % MOD;
        finv[i] = finv[i-1] * inv[i] % MOD;
    }
}
ll comb(int n, int k){
    if(n < k) return 0;
    if(n < 0 || k < 0) return 0;
    return fac[n] * finv[k] % MOD * finv[n-k] % MOD;
}

const int MAXkai = 200010;
ll kai_memo[MAXkai];
ll kai(ll N){
  if(kai_memo[N] != 0) return kai_memo[N];
  if(N <= 1) return 1;
  return kai_memo[N] = N * kai(N-1) % MOD;
}

ll disit(ll s, ll base = 10){
  ll res = 0;
  while(s){
    res++;
    s /= base;
  }
  return res;
}

//約数の列挙O(√n)
vector<int> divisor(int n){
    vector<int> res(0);
    for(int i = 1; i * i <= n; i++){
        if(n % i == 0){
            res.push_back(i);
            if(i != n/i) res.push_back(n/i);
        }
    }
    sort(res.begin(), res.end());
    return res;
}

int N, M;
vector<int> dif;
struct edge{int to, id;};
vector<int> ans;
vector<edge> E[100010];
bool used[100010];
int dfs(int now){
  used[now] = 1;
  int res = dif[now];
  for(edge e: E[now])if(!used[e.to]){
    int r = dfs(e.to);
    if(r){
      res ^= 1;
      ans.pb(e.id);
    }
  }
  return res;
}

void solve(){
  cin >> N >> M;
  vector<pair<int, int>> AB(N);
  rep(i, N) cin >> AB[i].f >> AB[i].s;
  sort(AB.begin(), AB.end());
  vector<pair<int, int>> code;
  rep(i, M){
    ll l, r;
    cin >> l >> r;
    int left = lower_bound(AB.begin(), AB.end(), pair<int, int>{l, -1}) - AB.begin();
    int right = lower_bound(AB.begin(), AB.end(), pair<int, int>{r, INF}) - AB.begin();
    code.pb({left, right});
    E[left].pb({right, i});
    E[right].pb({left, i});
  }


  dif.resize(N+1, 0);
  dif[0] = AB[0].s;
  for(int i = 1; i < N; i++){
    dif[i] =  AB[i-1].s ^ AB[i].s;
  }
  dif[N] = AB[N-1].s;

  for(int i = 0; i <= N; i++){
    if(used[i]) continue;
    if(dfs(i)){
      cout << -1 << endl;
      return;
    }
  }
  sort(ans.begin(), ans.end());
  cout << sz(ans) << endl;
  rep(i, sz(ans)){
    cout << ans[i]+1;
    if(i == sz(ans)-1) cout << endl;
    else cout << " ";
  }
}

int main(){
  ios_base::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  solve();
}


Measured memory_bytes: 17520