#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
void init_ios() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
}
const int N = (1 << 19);
int n, m, jump[N][20];
pair<int, int> a[N], drz[2 * N];
void add(int v, int val, int ind) {
  v += N;
  if (val < drz[v].first) return;
  drz[v] = {val, ind};
  while (v > 1) {
    v /= 2;
    if (drz[2 * v].first > drz[2 * v + 1].first)
      drz[v] = drz[2 * v];
    else
      drz[v] = drz[2 * v + 1];
  }
}
pair<int, int> get(int p, int q) {
  p += N;
  q += N;
  pair<int, int> res;
  if (drz[p].first > drz[q].first)
    res = drz[p];
  else
    res = drz[q];
  while (p / 2 != q / 2) {
    if (p % 2 == 0 && drz[p + 1].first > res.first) res = drz[p + 1];
    if (q % 2 == 1 && drz[q - 1].first > res.first) res = drz[q - 1];
    p /= 2;
    q /= 2;
  }
  return res;
}
int get_id(int id, int hm) {
  for (int i = 0; i < 20; ++i)
    if (hm & (1 << i)) id = jump[id][i];
  return id;
}
int query(int x, int y) {
  int id = get(0, x).second;
  if (id == 0) return -1;
  if (a[id].second >= y) return 1;
  int x1 = 1, x2 = n - 1, x3;
  while (x2 - x1 > 1) {
    x3 = (x1 + x2) / 2;
    int id2 = get_id(id, x3);
    if (id2 == 0 || a[id2].second >= y)
      x2 = x3;
    else
      x1 = x3;
  }
  int id2 = get_id(id, x1);
  if (id2 != 0 && a[id2].second >= y) return 1 + x1;
  id2 = get_id(id, x2);
  if (id2 != 0 && a[id2].second >= y) return 1 + x2;
  return -1;
}
int main() {
  init_ios();
  cin >> n >> m;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i].first >> a[i].second;
    add(a[i].first, a[i].second, i);
  }
  for (int l = 0; l < 20; ++l) {
    for (int i = 1; i <= n; ++i) {
      if (l == 0) {
        pair<int, int> p = get(a[i].first, a[i].second);
        jump[i][l] = p.second;
      } else {
        jump[i][l] = jump[jump[i][l - 1]][l - 1];
      }
    }
  }
  while (m--) {
    int x, y;
    cin >> x >> y;
    cout << query(x, y) << "\n";
  }
}
