#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define fi first
#define se second
const int maxn = 1e5;
const int maxwidth = 2 * maxn;
const int inf = maxwidth + 1;
const int logn = 20;
void print_impossible() {
cout << "impossible\n";
return;
}
struct interval {
int l, r, id;
bool operator < (const interval & other) const {
return l < other.l;
}
};
const interval def = {inf, inf, 0};
vector<interval> v;
interval arr[1 + maxwidth];
interval tree[1 + 4 * maxwidth];
void reset() {
for(int i = 0; i <= maxwidth; i++) {
arr[i] = def;
}
for(int i = 0; i <= 4 * maxwidth; i++) {
tree[i] = def;
}
}
void build(int v, int vl, int vr) {
// cout << v << " " << vl << " " << vr << endl;
if(vl == vr) {
tree[v] = arr[vl];
return;
}
int mid = (vl + vr) / 2;
build(2 * v, vl, mid);
build(2 * v + 1, mid + 1, vr);
tree[v] = min(tree[2 * v], tree[2 * v + 1]);
}
interval query(int v, int vl, int vr, int ql, int qr) {
if(vr < ql || vl > qr) {
return def;
}
if(vl == ql && vr == qr) {
return tree[v];
}
int mid = (vl + vr) / 2;
return min(query(2 * v, vl, mid, ql, min(qr, mid)), query(2 * v + 1, mid + 1, vr, max(ql, mid + 1), qr));
}
int n, q;
vector<pii > queries;
int par[1 + maxn];
int lift[1 + maxn][logn];
void compress() {
vector<int> comp;
for(const interval &cur : v) {
comp.pb(cur.l), comp.pb(cur.r);
}
sort(comp.begin(), comp.end());
comp.resize(unique(comp.begin(), comp.end()) - comp.begin());
for(interval &cur : v) {
cur.l = (lower_bound(comp.begin(), comp.end(), cur.l) - comp.begin()) + 1;
cur.r = (lower_bound(comp.begin(), comp.end(), cur.r) - comp.begin()) + 1;
}
return;
}
bool can_step(const interval &a, const interval &b) {
return (b.l <= a.r && a.r <= b.r);
}
int ans_query(int s, int e) {
if(s == e) {
return 0;
}
interval si = v[s - 1], ei = v[e - 1];
if(si.r > ei.r) {
return -1;
}
if(can_step(si, ei)) {
return 1;
}
int cur = e, cnt = 0;
for(int j = logn - 1; j >= 0; j--) {
int possible_new_candidate_option = lift[cur][j];
if(possible_new_candidate_option == 0) {
continue;
}
interval other = v[possible_new_candidate_option - 1];
if(other.l > si.r) {
cur = possible_new_candidate_option;
cnt += (1 << j);
}
}
cur = par[cur];
cnt++;
if(!can_step(si, v[cur - 1])) {
return -1;
}
cnt++;
return cnt;
}
void solve() {
cin >> n >> q;
for(int i = 1; i <= n; i++) {
int l, r;
cin >> l >> r;
v.pb({l, r, i});
}
for(int i = 1; i <= q; i++) {
int s, e;
cin >> s >> e;
queries.pb({s, e});
}
compress();
reset();
for(const interval &cur : v) {
arr[cur.r] = min(arr[cur.r], cur);
}
/*for(const interval &cur : v) {
cout << cur.l << " " << cur.r << " " << cur.id << endl;
}*/
build(1, 1, maxwidth);
//cout << "here" << endl;
for(const interval &cur : v) {
par[cur.id] = query(1, 1, maxwidth, cur.l, cur.r).id;
}
/*for(int i = 1; i <= n; i++) {
cout << par[i] << " ";
}
cout << endl;*/
for(int i = 1; i <= n; i++) {
lift[i][0] = par[i];
}
for(int j = 1; j < logn; j++) {
for(int i = 1; i <= n; i++) {
lift[i][j] = lift[lift[i][j - 1]][j - 1];
}
}
for(const pii &p : queries) {
int s = p.fi, e = p.se;
int res = ans_query(s, e);
if(res == -1) {
print_impossible();
} else {
cout << res << "\n";
}
}
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
solve();
return 0;
}
