#include <bits/stdc++.h>
using namespace std;
const int maxn = 500005;
const int mod = 1e9 + 7;
pair<int, int> a[maxn];
vector<pair<int, int> > v;
int f[maxn][25], n, m;
int check(int k, int x) {
  for (int i = (0); i < (21); i++)
    if ((x >> i) & 1) {
      k = f[k][i];
    }
  return v[k].second;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> m;
  for (int i = (1); i < (n + 1); i++) {
    cin >> a[i].first >> a[i].second;
  }
  int M = 1e6 + 1;
  sort(a + 1, a + 1 + n);
  v.push_back(a[1]);
  for (int i = (2); i < (n + 1); i++) {
    if (a[i].first == v.back().first)
      v[(int)v.size() - 1].second = a[i].second;
    else if (a[i].second > v.back().second)
      v.push_back(a[i]);
  }
  for (int i = (0); i < ((int)v.size()); i++) {
    int k = upper_bound(v.begin(), v.end(), make_pair(v[i].second, M)) -
            v.begin() - 1;
    f[i][0] = k;
  }
  for (int i = 1; i <= 20; i++)
    for (int j = (0); j < ((int)v.size()); j++) f[j][i] = f[f[j][i - 1]][i - 1];
  while (m--) {
    int x, y;
    cin >> x >> y;
    if (x < v[0].first || y > v.back().second) {
      cout << -1 << "\n";
      continue;
    }
    int k = upper_bound(v.begin(), v.end(), make_pair(x, M)) - v.begin() - 1;
    int l = 0, r = (1 << 20) - 1, ans = -1;
    while (l <= r) {
      int mid = l + r >> 1;
      if (check(k, mid) >= y)
        r = mid - 1, ans = mid;
      else
        l = mid + 1;
    }
    if (ans == -1)
      cout << "-1\n";
    else
      cout << 1 + ans << "\n";
  }
  return 0;
}
