#include <bits/stdc++.h>
using namespace std;
struct station {
int nxt, best;
bool operator<(const station &x) const {
return best < x.best;
}
};
struct train {
int a, b;
bool operator<(const train &x) const {
if (b == x.b)
return a < x.a;
return b < x.b;
}
};
const int MAX_N = 1e5;
const int MAX_LOG_N = 16;
const int MAX_M = 2e5;
train trains[MAX_M];
station maxReachGlobal[MAX_LOG_N + 1][MAX_N + 1];
int reachByOneTrain[MAX_N + 1];
int nextStationRight[MAX_LOG_N + 1][MAX_N + 1];
priority_queue<train> bestTrains;
vector<train> trainsByTime[MAX_N + 1];
station queryMax(int l, int r) {
int p = log2(r - l + 1);
return max(maxReachGlobal[p][l], maxReachGlobal[p][r - (1 << p) + 1]);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, k, m;
cin >> n >> k >> m;
for (int i = 0; i < m; i++) {
cin >> trains[i].a >> trains[i].b;
trainsByTime[min(n, trains[i].a + k - 1)].push_back(trains[i]);
}
for (int i = n; i >= 1; i--) {
maxReachGlobal[0][i] = {i, i};
reachByOneTrain[i] = i;
for (train t: trainsByTime[i])
bestTrains.push(t);
while (!bestTrains.empty() && bestTrains.top().a > i)
bestTrains.pop();
if (!bestTrains.empty()) {
reachByOneTrain[i] = bestTrains.top().b;
/* printf("one train %d %d\n", i, reachByOneTrain[i]); */
maxReachGlobal[0][i] = queryMax(i, reachByOneTrain[i]);
}
nextStationRight[0][i] = maxReachGlobal[0][i].nxt;
maxReachGlobal[0][i].nxt = i;
for (int l = 1; (1 << l) <= n - i + 1; l++)
maxReachGlobal[l][i] = max(maxReachGlobal[l - 1][i], maxReachGlobal[l - 1][i + (1 << (l - 1))]);
/* printf("next %d %d\n", i, nextStationRight[0][i]); */
}
for (int l = 1; (1 << l) <= n; l++) {
for (int i = 1; i <= n; i++)
nextStationRight[l][i] = nextStationRight[l - 1][nextStationRight[l - 1][i]];
}
int q;
cin >> q;
for (int i = 0; i < q; i++) {
int a, b;
cin >> a >> b;
int ans = 0;
for (int l = log2(n); l >= 0; l--) {
if (reachByOneTrain[nextStationRight[l][a]] < b) {
ans += (1 << l);
a = nextStationRight[l][a];
}
}
if (reachByOneTrain[nextStationRight[0][a]] < b)
cout << "-1\n";
else if (a >= b)
cout << ans << "\n";
else if (reachByOneTrain[a] >= b)
cout << ans + 1 << "\n";
else
cout << ans + 2 << "\n";
}
return 0;
}
