#include <algorithm>
#include <iostream>
#include <tuple>
#include <unordered_set>
#include <utility>
#include <vector>
using i64 = int64_t;
int main() {
std::cin.tie(nullptr)->sync_with_stdio(false);
i64 n, q;
std::cin >> n >> q;
struct Point {
i64 time;
int type;
int idx;
bool operator<(const Point &rhs) const {
return std::tie(time, type, idx) <
std::tie(rhs.time, rhs.type, rhs.idx);
}
};
std::vector<std::vector<i64>> nexts(n);
std::unordered_set<i64> current;
std::vector<Point> points;
for (int i = 0; i < n; i++) {
i64 s, e;
std::cin >> s >> e;
points.push_back(Point{.time = s, .type = 0, .idx = i});
points.push_back(Point{.time = e, .type = 1, .idx = i});
points.push_back(Point{.time = e, .type = 2, .idx = i});
}
std::sort(points.begin(), points.end());
for (auto point : points) {
switch (point.type) {
case 0:
current.insert(point.idx);
break;
case 1:
nexts[point.idx].insert(nexts[point.idx].end(), current.begin(),
current.end());
break;
case 2:
current.erase(point.idx);
break;
}
}
std::vector<bool> visited(n);
std::vector<i64> next;
std::vector<i64> more;
for (i64 i = 0; i < q; i++) {
int s, e;
std::cin >> s >> e;
s--, e--;
std::fill(visited.begin(), visited.end(), false);
next.clear();
more.clear();
next.push_back(s);
visited[s] = true;
for (i64 time = 0; !next.empty(); time++) {
for (i64 node : next) {
if (node == e) {
std::cout << time << '\n';
goto next;
}
for (i64 possible : nexts[node]) {
if (!visited[possible]) {
visited[possible] = true;
more.push_back(possible);
}
}
}
std::swap(next, more);
more.clear();
}
std::cout << "impossible\n";
next:;
}
}
