#include <bits/stdc++.h>
bool local = false;
using namespace std;
template <class T>
string toString(T x) {
  ostringstream sout;
  sout << x;
  return sout.str();
}
template <class T>
void print(T v) {
  cout << ((int)(v).size()) << "\n";
  for (auto x : v) cout << x << ' ';
  cout << "\n";
};
template <class T1, class T2>
ostream &operator<<(ostream &o, pair<T1, T2> x) {
  return o << x.first << ' ' << x.second;
}
template <class T1, class T2>
istream &operator>>(istream &o, pair<T1, T2> &x) {
  return o >> x.first >> x.second;
}
template <class T1, class T2>
pair<T1, T2> operator+(pair<T1, T2> a, pair<T1, T2> b) {
  a.first += b.first;
  a.second += b.second;
  return a;
}
template <class T1, class T2>
pair<T1, T2> operator-(pair<T1, T2> a, pair<T1, T2> b) {
  a.first -= b.first;
  a.second -= b.second;
  return a;
}
template <class T1, class T2>
void operator+=(pair<T1, T2> &a, pair<T1, T2> b) {
  a.first += b.first;
  a.second += b.second;
}
template <class T1, class T2>
void operator-=(pair<T1, T2> &a, pair<T1, T2> b) {
  a.first -= b.first;
  a.second -= b.second;
}
int nint() {
  int x;
  cin >> x;
  return x;
}
double getTime() { return clock() / (double)CLOCKS_PER_SEC; };
mt19937 rnd(0);
int rand(int n) { return rnd() % n; }
int rand(int l, int r) { return rnd() % (r - l + 1) + l; }
const int mod = 1000000000 + 7;
void initIO() {
  if (local) {
    freopen("input.txt", "r", stdin);
    srand((int)time(0));
    rnd.seed((int)time(0));
  } else {
  }
  {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
  };
}
int m;
int n;
vector<pair<int, int> > v;
vector<int> v1, v2;
const int K = 19;
bool f(pair<int, int> a, pair<int, int> b) {
  if (a.first != b.first) return a.first < b.first;
  return a.second > b.second;
}
vector<pair<int, int> > update(vector<pair<int, int> > v) {
  vector<pair<int, int> > ans;
  ans.emplace_back(v[0]);
  for (int i = 1; i < ((int)(v).size()); i++) {
    pair<int, int> x = ans.back();
    pair<int, int> y = v[i];
    if (y.second <= x.second) continue;
    ans.emplace_back(y);
  }
  return ans;
}
int get(int x) {
  int p = upper_bound(v1.begin(), v1.end(), x) - v1.begin() - 1;
  if (p == -1) return -1;
  return p;
}
int ne[K + 1][200500];
void calc() {
  for (int i = 0; i < (n); i++) ne[0][i] = i;
  for (int t = 1; t < K; t++) {
    for (int i = 0; i < (n); i++) {
      int x = v2[ne[t - 1][i]];
      int id = get(x);
      x = ne[t - 1][id];
      ne[t][i] = x;
    }
  }
}
int getans(int x, int y) {
  int p = get(x);
  if (p == -1) return -1;
  int ans = 1;
  for (int i = K - 1; i > 0; i--) {
    while (1) {
      int np = ne[i][p];
      if (p == np) break;
      if (v2[np] < y) {
        p = np;
        ans += (1 << i) - 1;
      } else
        break;
    }
  }
  if (v2[p] < y) {
    p = ne[1][p];
    ans++;
  }
  if (v[p].second < y) return -1;
  return ans;
}
int main() {
  initIO();
  cin >> n >> m;
  for (int i = 0; i < (n); i++) {
    int l, r;
    cin >> l >> r;
    v.emplace_back(l, r);
  }
  sort(v.begin(), v.end(), f);
  v = update(v);
  n = ((int)(v).size());
  for (int i = 0; i < (n); i++) {
    v1.emplace_back(v[i].first);
    v2.emplace_back(v[i].second);
  };
  ;
  ;
  ;
  calc();
  for (int i = 0; i < (m); i++) {
    int l, r;
    cin >> l >> r;
    cout << getans(l, r) << "\n";
  }
}
