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

#define endl '\n'
#define lfs cout<<fixed<<setprecision(10)
#define ALL(a)  (a).begin(),(a).end()
#define ALLR(a)  (a).rbegin(),(a).rend()
#define spa << " " <<
#define fi first
#define se second
#define MP make_pair
#define MT make_tuple
#define PB push_back
#define EB emplace_back
#define rep(i,n,m) for(ll i = (n); i < (ll)(m); i++)
#define rrep(i,n,m) for(ll i = (m) - 1; i >= (ll)(n); i--)
using ll = long long;
using ld = long double;
const ll MOD = 1e9+7;
//const ll MOD = 998244353;
const ll INF = 1e18;
using P = pair<ll, ll>;
template<typename T>
bool chmin(T &a,T b){if(a>b){a=b;return true;}else return false;}
template<typename T>
bool chmax(T &a,T b){if(a<b){a=b;return true;}else return false;}
ll median(ll a,ll b, ll c){return a+b+c-max({a,b,c})-min({a,b,c});}
void ans1(bool x){if(x) cout<<"Yes"<<endl;else cout<<"No"<<endl;}
void ans2(bool x){if(x) cout<<"YES"<<endl;else cout<<"NO"<<endl;}
void ans3(bool x){if(x) cout<<"Yay!"<<endl;else cout<<":("<<endl;}
template<typename T1,typename T2>
void ans(bool x,T1 y,T2 z){if(x)cout<<y<<endl;else cout<<z<<endl;}  
template<typename T>
void debug(vector<vector<T>>&v,ll h,ll w){for(ll i=0;i<h;i++)
{cout<<v[i][0];for(ll j=1;j<w;j++)cout spa v[i][j];cout<<endl;}};
void debug(vector<string>&v,ll h,ll w){for(ll i=0;i<h;i++)
{for(ll j=0;j<w;j++)cout<<v[i][j];cout<<endl;}};
template<typename T>
void debug(vector<T>&v,ll n){if(n!=0)cout<<v[0];
for(ll i=1;i<n;i++)cout spa v[i];cout<<endl;};
template<typename T>
vector<vector<T>>vec(ll x, ll y, T w){
  vector<vector<T>>v(x,vector<T>(y,w));return v;}
ll gcd(ll x,ll y){ll r;while(y!=0&&(r=x%y)!=0){x=y;y=r;}return y==0?x:y;}
vector<ll>dx={1,0,-1,0,1,1,-1,-1};
vector<ll>dy={0,1,0,-1,1,-1,1,-1};
template<typename T>
vector<T> make_v(size_t a,T b){return vector<T>(a,b);}
template<typename... Ts>
auto make_v(size_t a,Ts... ts){
  return vector<decltype(make_v(ts...))>(a,make_v(ts...));
}
ostream &operator<<(ostream &os, pair<ll, ll>&p){
  return os << p.first << " " << p.second;
}  
struct UnionFind {
  vector<ll> data;
  ll num;
  UnionFind(ll size) : data(size, -1) ,num(size){ }
  bool unite(ll x, ll y) {
    x = root(x); y = root(y);
    if (x != y) {
      if (data[y] < data[x]) swap(x, y);
      data[x] += data[y]; data[y] = x;
	  num--;
    }
    return x != y;
  }
  bool find(ll x, ll y) {
    return root(x) == root(y);
  }
  ll root(ll x) {
    return data[x] < 0 ? x : data[x] = root(data[x]);
  }
  ll size(ll x) {
    return -data[root(x)];
  }
};

struct edge{
  ll to,id;
  edge(){};
  edge(ll t,ll c):to(t),id(c){};
};
struct HLD{
  ll n, root;
  ll cnt = 0;
  vector<ll>sz;//部分木サイズ
  vector<ll>depth;//深さ
  vector<ll>par,head;
  vector<vector<struct edge>>g;//隣接リスト
  vector<struct edge>edges;//データ構造に乗せるedge列
  vector<ll>in,out;//[in,out)で部分木、[ina,inb]でa~bのパス(aが上)
  //inは頂点のindexを表す。また、edge列の下側の頂点である
  HLD(vector<vector<struct edge>>G,ll r = -1)
      :g(G),n(G.size()),root(r){
    depth.assign(n,-1),par.assign(n,-1),in.assign(n,-1);
    out.assign(n,-1),head.assign(n,-1),sz.assign(n,-1);
    edges.assign(n,edge());
    dfs_build();
  }
  void dfs_build(){
    if(root == -1){//根がどこでも良い場合(森でも可)
      for(ll i=0;i<n;i++){
        if(sz[i] == -1){
          head[i] = i;
          dfs_sz(i,0);
          dfs_hld(i);
        }
      }
    }
    else{
      head[root] = root;
      dfs_sz(root,0);
      dfs_hld(root);
    }
  }
  void dfs_sz(ll k, ll d){
    depth[k] = d;
    sz[k] = 1;
    for(auto &e: g[k]){
      if(e.to == par[k])continue;
      par[e.to] = k;
      dfs_sz(e.to,d+1);
      sz[k] += sz[e.to];
      if(sz[e.to] > sz[g[k][0].to])swap(e, g[k][0]);
    }
  }
  void dfs_hld(ll k){
    in[k] = cnt++;
    for(auto e:g[k]){
      if(e.to == par[k])continue;
      head[e.to] = (e.to == g[k][0].to ? head[k]: e.to);
      edges[cnt] = e;
      dfs_hld(e.to);
    }
    out[k] = cnt;
  }
  ll lca(ll p,ll q){
    while(1){
      if(depth[head[p]] < depth[head[q]])swap(p,q);
      if(head[p] == head[q])break;
      p = par[head[p]];
    }
    if(depth[p] > depth[q])swap(p,q);
    return p;
  }
  vector<pair<ll,ll>>query_path(ll p,ll q,bool isEdge=true){
    ll r=lca(p,q);
    vector<pair<ll,ll>>ret;
    for(ll i=0;i<2;i++){
      if(i == 1)swap(p,q);
      while(1){
        if(isEdge&&p==r)break;
        if(head[p]==head[r]){
          ret.emplace_back(in[r]+(isEdge?1:i),in[p]+1);
          break;
        }
        ret.emplace_back(in[head[p]],in[p]+1);
        p = par[head[p]];
      }
    }
    return ret;
  }

  pair<ll,ll>query_subtree(ll p,bool isEdge=true){
    return MP(in[p]+isEdge,out[p]);
  }
};
template<typename T>
map<T,ll> compress(vector<T> &v){
  auto t=v;
  sort(ALL(t));
  t.erase(unique(ALL(t)),t.end());
  map<T, ll> ret;
  for(ll i=0;i<(ll)t.size();i++)
    ret[t[i]]=i;
  return ret;
}
int main(){
  cin.tie(nullptr);
  ios_base::sync_with_stdio(false);
  ll res=0,buf=0;
  bool judge = true;
  ll n,m;cin>>n>>m;
  vector<P>a(n);
  vector<ll>vals(n);
  rep(i,0,n)cin>>a[i].fi>>a[i].se;
  rep(i,0,n)vals[i]=a[i].fi;
  auto mp=compress(vals);
  sort(ALL(a));
  vector<ll>v(mp.size()+1);
  ll sz=mp.size();
  UnionFind uf(sz+1);
  vector<vector<edge>>g(sz+1);
  rep(i,0,m){
    ll l,r;cin>>l>>r;
    auto litr=mp.lower_bound(l);
    ll lidx;
    if(litr!=mp.end())lidx=litr->se;
    else continue;
    auto ritr=mp.upper_bound(r);
    ll ridx;
    if(ritr==mp.end())ridx=sz;
    else ridx=ritr->se;
    if(uf.unite(lidx,ridx)){
      g[lidx].EB(ridx,i);
      g[ridx].EB(lidx,i);
    }
  }
  vector<vector<ll>>ver(sz+1);
  vector<vector<ll>>cha(sz+1);
  rep(i,0,sz+1)ver[uf.root(i)].PB(i);
  vector<ll>cnt(sz+1);
  rep(i,0,n)if(a[i].se==1)cnt[mp[a[i].fi]]^=1;
  rep(i,0,sz+1){
    if(i==0){
      if(cnt[i]==1)cha[uf.root(i)].PB(i);
    }
    else if(cnt[i-1]!=cnt[i]){
      cha[uf.root(i)].PB(i);
    }
  }
  vector<ll>ret;
  /*rep(i,0,sz+1)if(cha[i].size()>=1){
    debug(cha[i],cha[i].size());
    debug(ver[i],ver[i].size());
  }*/
  rep(i,0,sz+1){
    if((ll)cha[i].size()&1){
      judge=false;
      break;
    }
    if(cha[i].size()==0)continue;
    ll n=ver[i].size();
    map<ll,ll>idx;
    rep(j,0,n)idx[ver[i][j]]=j;
    vector<vector<edge>>gt(n);
    rep(j,0,n){
      for(auto e:g[ver[i][j]]){
        gt[j].EB(idx[e.to],e.id);
      }
    }
    HLD hld(gt,0);
    vector<ll>imos(hld.edges.size()+1);
    rep(j,0,(ll)cha[i].size()/2){
      auto v=hld.query_path(idx[cha[i][2*j]],idx[cha[i][2*j+1]]);
      for(auto p:v){
        //cout<<p.fi spa p.se<<endl;
        imos[p.fi]^=1;
        imos[p.se]^=1;
      }
      //debug(imos,n);
    }
    //debug(hld.sz,n);
    //debug(hld.in,n);
    //debug(hld.out,n);
    rep(i,0,(ll)imos.size()-1)imos[i+1]^=imos[i];
    rep(i,0,hld.edges.size()){
      auto e=hld.edges[i];
      if(imos[i])ret.PB(e.id+1);
    }
  }
  if(!judge){
    cout<<-1<<endl;
    return 0;
  }
  sort(ALL(ret));
  cout<<ret.size()<<endl;
  debug(ret,ret.size());
  return 0;
}

Measured memory_bytes: 58480