#include <iostream>
#include <vector>
using namespace std;
struct event {
int s, e;
};
int n, q, a, b;
vector <event> v(5001);
vector <vector <int>> g(1e5 + 1);
vector <vector <int>> d(5001, vector <int>(5001, 1e9));
vector <bool> done(5001, false);
void dfs(int x) {
if (done[x]) return;
done[x] = true;
for (int i : g[x]) {
dfs(i);
for (int j = 1; j <= n; j++) d[x][j] = min(d[x][j], d[i][j] + 1);
}
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> q;
if (n > 5000) return 0;
for (int i = 1; i <= n; i++) {
cin >> v[i].s >> v[i].e;
d[i][i] = 0;
}
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
if (v[i].e >= v[j].s && v[i].e <= v[j].e) g[i].push_back(j);
}
}
for (int i = 1; i <= n; i++) dfs(i);
for (int i = 0; i < q; i++) {
cin >> a >> b;
if (d[a][b] < 1e9) cout << d[a][b] << "\n";
else cout << "impossible\n";
}
}
