#include "bits/stdc++.h"
using namespace std;
const int N = 5000;
int dist[N][N];
int l[N], r[N], n, q;
vector<int> events[2 * N + 5];
void go(int start) {
queue<int> q;
vector<bool> closed(n, false);
q.push(start);
dist[start][start] = 0;
for(int i = r[start]; i >= 0; --i) {
while(!q.empty() && closed[q.front()]) q.pop();
for(int e: events[i]) {
if(e == start) continue;
if(e < 0) continue;
if(!q.empty()) {
dist[start][e] = dist[start][q.front()] + 1;
q.push(e);
}
}
for(int e: events[i]) {
if(e >= 0) continue;
int idx = -e - 1;
closed[idx] = true;
}
}
}
int main() {
vector<int> v;
cin >> n >> q;
for(int i = 0; i < n; ++i) {
cin >> l[i] >> r[i];
v.push_back(l[i]);
v.push_back(r[i]);
}
sort(v.begin(), v.end());
v.erase(unique(v.begin(), v.end()), v.end());
for(int i = 0; i < n; ++i) {
l[i] = lower_bound(v.begin(), v.end(), l[i]) - v.begin();
r[i] = lower_bound(v.begin(), v.end(), r[i]) - v.begin();
events[r[i]].push_back(i);
events[l[i]].push_back(-i - 1);
}
for(int i = 0; i < N; ++i) for(int j = 0; j < N; ++j) dist[i][j] = -1;
for(int i = 0; i < n; ++i) go(i);
while(q--) {
int a, b; cin >> a >> b; --a, --b;
if(dist[b][a] == -1) cout << "impossible\n";
else cout << dist[b][a] << "\n";
}
}
