#include "bits/stdc++.h"
#include <valarray>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define DEBUG 1
#define MULTI_TEST 0
struct Node {
int l{}, r{};
Node() { this->l = 1e9, this->r = -1; }
Node(int l, int r) { this->l = l, this->r = r; }
Node(int x) { this->l = x, this->r = x; }
Node operator+(const Node& other) {
return Node(min(this->l, other.l), max(this->r, other.r));
}
};
struct SegmentTree {
vector<Node> leafs;
vector<Node> node;
void build(int n, vector<Node>& vec) {
leafs = vec;
node.resize(4 * n);
auto build = [&](auto&& build, int id, int l, int r) -> void {
if (l == r) node[id] = vec[l];
else {
int mid = (l + r) / 2;
build(build, id * 2, l, mid);
build(build, id * 2 + 1, mid + 1, r);
node[id] = node[id * 2] + node[id * 2 + 1];
}
};
build(build, 1, 0, n - 1);
}
void update(int id, int l, int r, int pos, int val) {
if (l == r) node[id] = val;
else {
int mid = (l + r) / 2;
if (pos <= mid) update(id * 2, l, mid, pos, val);
else update(id * 2 + 1, mid + 1, r, pos, val);
}
}
Node query(int id, int l, int r, int L, int R) {
if (l > R || r < L) return Node();
else if (L <= l && r <= R) return node[id];
else {
int mid = (l + r) / 2;
return query(id * 2, l, mid, L, R) + query(id * 2 + 1, mid + 1, r, L, R);
}
}
};
int main() {
cin.tie(0)->sync_with_stdio(0);
int n, k;
cin >> n >> k;
int m;
cin >> m;
int lgn = 0;
while (1 << (lgn + 1) <= n) {
++lgn;
}
++lgn;
++lgn;
vector<SegmentTree> segtree(lgn);
vector<int> right_train(n, -1);
vector<int> left_train(n, -1);
for (int i = 0; i < m; i++) {
int ai{}, bi{};
cin >> ai >> bi;
--ai, --bi;
if (bi > ai) {
if (right_train[ai] == -1) right_train[ai] = bi;
else right_train[ai] = max(right_train[ai], bi);
}
else {
if (left_train[ai] == -1) left_train[ai] = bi;
else left_train[ai] = min(left_train[ai], bi);
}
}
vector<Node> initial_step(n);
for (int i = 0; i < n; i++) initial_step[i] = Node(i);
deque<pair<int, int>> Q;
for (int i = 0; i < n; i++) {
if (right_train[i] != -1) {
while (!Q.empty() && right_train[i] > Q.back().second) Q.pop_back();
Q.push_back({i, right_train[i]});
}
while (!Q.empty() && Q.front().first + k <= i) Q.pop_front();
while (!Q.empty() && Q.front().second <= i) Q.pop_front();
if (!Q.empty()) initial_step[i].r = Q.front().second;
}
Q.clear();
for (int i = n - 1; i >= 0; i--) {
if (left_train[i] != -1) {
while (!Q.empty() && left_train[i] < Q.back().second) Q.pop_back();
Q.push_back({i, left_train[i]});
}
while (!Q.empty() && Q.front().first - k >= i) Q.pop_front();
while (!Q.empty() && Q.front().second >= i) Q.pop_front();
if (!Q.empty()) initial_step[i].l = Q.front().second;
}
segtree[0].build(n, initial_step);
for (int i = 1; i < lgn; i++) {
vector<Node> new_step(n);
for (int j = 0; j < n; j++) {
new_step[j] = segtree[i - 1].leafs[j];
new_step[j] = segtree[i - 1].query(1, 0, n - 1, new_step[j].l, new_step[j].r);
}
segtree[i].build(n, new_step);
}
// for (int i = 0; i < lgn; i++) {
// cout << "Step " << (1 << i) << "\n";
// for (int j = 0; j < n; j++) {
// cout << "Pos " << j << " : " << segtree[i].leafs[j].l << " " << segtree[i].leafs[j].r << endl;
// }
// }
int q;
cin >> q;
for (int i = 0; i < q; i++) {
int si{}, ti{};
cin >> si >> ti;
--si, --ti;
Node end_range = segtree[lgn - 1].leafs[si];
if (end_range.l > ti || end_range.r < ti) {
cout << -1 << "\n";
continue;
}
int ans = 1 << (lgn - 1);
int cur = 0;
Node cur_range = {si, si};
for (int i = lgn - 1; i >= 0; i--) {
Node new_range = segtree[i].query(1, 0, n - 1, cur_range.l, cur_range.r);
if (new_range.l > ti || new_range.r < ti) { // not reach
cur += 1 << i;
cur_range = new_range;
}
else { // reach
ans = min(ans, cur + (1 << i));
}
}
cout << ans << "\n";
}
}
