// Problem : F - Perils in Parallel
// Contest : AtCoder - AtCoder Beginner Contest 155
// URL : https://atcoder.jp/contests/abc155/tasks/abc155_f
// Memory Limit : 1024 MB
// Time Limit : 2000 ms
// Powered by CP Editor (https://github.com/cpeditor/cpeditor)

#include <iostream>
#include <bitset>
using std::to_string;
std::string to_string(const std::string &s) { return '"' + s + '"'; }

std::string to_string(const char *s) { return to_string((std::string) s); }

std::string to_string(bool b) { return (b ? "true" : "false"); }

template<typename A, typename B>
std::string to_string(const std::pair<A, B> &p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template<size_t N>
std::string to_string(const std::bitset<N> &bs) {
  return bs.to_string();
}
template<typename A>
std::string to_string(const A &v) {
  bool first = true;
  std::string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

void debug_out() { std::cerr << std::endl; }

template<typename Head, typename... Tail>
void debug_out(const Head &H, const Tail &... T) {
  std::cerr << " " << to_string(H);
  debug_out(T...);
}

#if defined LOCAL
#define debug(...) std::cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
#ifndef ALGO_UTILS
#define ALGO_UTILS
#include <algorithm>
#include <vector>
template<typename A, typename B>
bool chkmin(A &a, const B &b) {
  if (b < a) {
    a = b;
    return true;
  }
  return false;
}

template<typename A, typename B>
bool chkmax(A &a, const B &b) {
  if (b > a) {
    a = b;
    return true;
  }
  return false;
}

using ll = long long;
using ull = unsigned long long;
using vl = std::vector<ll>;
using vb = std::vector<bool>;
using vi = std::vector<int>;
using pii = std::pair<int, int>;
using pli = std::pair<ll, int>;
using pll = std::pair<ll, ll>;
template<typename T> using vv = std::vector<std::vector<T>>;
#define rng(i, a, b) for (std::common_type<decltype(a),decltype(b)>::type i = a; i < b; ++i)
#define up(i, a, b) for (std::common_type<decltype(a),decltype(b)>::type  i = a; i <= b; ++i)
#define down(i, b, a) for (std::common_type<decltype(a),decltype(b)>::type i = b; i >= a; i--)
#define TOKENPASTE(x, y) x##y
#define TOKENPASTE2(x, y) TOKENPASTE(x, y)
#define rep(n)                                                                 \
  for (int TOKENPASTE2(_iter_, __LINE__) = 0,                                  \
                               TOKENPASTE2(_num_, __LINE__) = n;        \
       TOKENPASTE2(_iter_, __LINE__) < TOKENPASTE2(_num_, __LINE__);           \
       ++TOKENPASTE2(_iter_, __LINE__))
#define FOR(x, cont) for (const auto &x : cont)
#define For(x, cont) for (auto &x : cont)
#define all(x) begin(x), end(x)
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define ep emplace
#define SZ(x) (int)(x).size()
#define UNIQ(vec) (vec).erase(std::unique(all(vec)), std::end(vec))
#define LB(cont, x) int(std::lower_bound(all(cont), x) - std::begin(cont))
#define UB(cont, x) int(std::upper_bound(all(cont), x) - std::begin(cont))
#endif
#ifndef JHELPER_EXAMPLE_PROJECT_LIBRARY_IO_HPP_
#define JHELPER_EXAMPLE_PROJECT_LIBRARY_IO_HPP_
#include <iostream>
#include <iomanip>
struct fast_ios {
  fast_ios() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed << std::setprecision(10);
  };
} fast_ios_;

template<typename T>
std::istream &operator>>(std::istream &stream, std::vector<T> &vec) {
  for (auto &x : vec)
    stream >> x;
  return stream;
}

template<typename T, typename U>
std::istream &operator>>(std::istream &in, std::pair<T, U> &p) {
  in >> p.first >> p.second;
  return in;
}

void scan() {}

template<class T, class... Args>
void scan(T &a, Args &... rest) {
  std::cin >> a;
  scan(rest...);
}

template<typename T>
std::ostream &operator<<(std::ostream &stream, const std::vector<T> &vec) {
  bool first = true;
  for (const T &t : vec) {
    if (first) first = false;
    else std::cout << ' ';
    std::cout << t;
  }
  return stream;
}

template<typename T>
void print(const std::vector<T> &t) {
  std::cout << t << '\n';
}

template<typename T>
void print(const std::vector<std::vector<T>> &t) {
  for (const auto &row : t) {
    print(row);
  }
}

template<typename T>
void print(const T &t) { std::cout << t << ' '; }

template<typename T, typename... Args>
void print(const T &t, const Args &... rest) {
  print(t);
  print(rest...);
}

template<typename T>
void println(const T &t) { std::cout << t << '\n'; }

template<typename T, typename... Args>
void println(const T &t, const Args &... rest) {
  print(t);
  println(rest...);
}
#endif //JHELPER_EXAMPLE_PROJECT_LIBRARY_IO_HPP_
#include <functional>
using namespace std;
int main() {
    int n,m;
    scan(n,  m);
    vector<pii> bombs(n);
    rng (i, 0, n) scan(bombs[i]);
    sort(all(bombs));
    vi pos(n);
    rng (i, 0, n) pos[i] = bombs[i].first;
    vi c(n+1);
    c[0] = bombs[0].second^0;
    rng (i, 1, n) c[i] = bombs[i].second^bombs[i-1].second;
    c[n] = bombs[n-1].second;
    vv<pii> g(n+1);
    up (i, 1, m) {
      int l, r; scan(l, r );
      int x = LB(pos,l);
      int y = UB(pos,r);
      if (x == y) continue;
      g[x].eb(y, i);
      g[y].eb(x, i);  
    }
    vb vis(n);
    vi edges;
    function<void(int)> dfs = [&](int u) {
        vis[u]=true;
        FOR (e, g[u]) {
            int v = e.first;
            if (!vis[v]) {
                dfs(v);
                if (c[v]) {
                    c[u] ^= 1;
                    edges.pb(e.second);
                }
            }
        }
    };
    rng (i, 0, n+1) if (!vis[i]) {
        dfs(i);
        if (c[i]) {
            println(-1);
            return 0;
        }
    }
    sort(all(edges));
    println(SZ(edges));
    print(edges);
    return 0;
}

Measured memory_bytes: 15612