#include <bits/stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> typedef long long ll; using namespace __gnu_pbds; using namespace std; template <typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; int M = 100'000; vector<pair<int, int>> seg(M); int base = 1<<19; vector<int> T(2*base, -1); int zmaksuj(int a, int b) { if(a==-1) return b; if(b==-1) return a; if(seg[a].second < seg[b].second) return b; return a; } void update(int a, int b, int val) { if(a>b) return; if(a==b) T[a+base] = zmaksuj(T[a+base], val); a+=base-1; b+=base+1; while(a/2!=b/2) { if(a%2==0) T[a+1] = zmaksuj(T[a+1], val); if(b%2==1) T[b-1] = zmaksuj(T[b-1], val); a/=2; b/=2; } } int query(int x) { x += base; ll ans = -1; while(x>0) { ans = zmaksuj(ans, T[x]); x/=2; } return ans; } void parse_input(int n) { map<int, vector<int>> konce; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); int n, q; cin >> n >> q; ll inf = 1e9; int maxlog = 16; vector<vector<int>> jump(n, vector<int>(maxlog+1)); vector<int> XY; for(int i=0; i<n; ++i) { cin >> seg[i].first >> seg[i].second; } parse_input(n); for(int i=0; i<n; ++i) { XY.push_back(seg[i].first); XY.push_back(seg[i].second); } sort(XY.begin(), XY.end()); for(int i=0; i<n; ++i) { update(lower_bound(XY.begin(), XY.end(), seg[i].first) - XY.begin(), lower_bound(XY.begin(), XY.end(), seg[i].second) - XY.begin(), i); // update(seg[i].first, seg[i].second, i); } for(int i=0; i<n; ++i) { jump[i][0] = query(lower_bound(XY.begin(), XY.end(), seg[i].second) - XY.begin()); // cout << i << ": " << jump[i][0] << "\n"; // jump[i][0] = query(seg[i].second); } for(int j=1; j<=maxlog; ++j) { for(int i=0; i<n; ++i) { jump[i][j] = jump[jump[i][j-1]][j-1]; } } while(q--) { int a, b; cin >> a >> b; --a;--b; if(a==b) { cout << "0\n"; continue; } int res = 0; for(int i=maxlog; i>=0; --i) { // if(i>0 && jump[a][i]==jump[a][i-1]) continue; if(seg[jump[a][i]].second < seg[b].second) { res += 1<<i; a = jump[a][i]; } } // cout << a << " " << res << " - " << jump[a][0] << "\n"; if(seg[b].first <= seg[a].second && seg[a].second <= seg[b].second) cout << res+1 << "\n"; else { bool ok = 0; for(int i=0; i<n; ++i) if(seg[a].first <= seg[i].first && seg[i].first <= seg[a].second && seg[b].first <= seg[i].second && seg[i].second <= seg[b].second) { cout << res+2 << '\n'; ok = 1; break; } if(!ok) cout << "impossible\n"; } } return 0; }