#include <bits/stdc++.h>
#define ll long long
#define name "Railway Trip 2"
#define fi(i, a, b) for(int i = a; i <= b; ++i)
#define fid(i, a, b) for(int i = a; i >= b; --i)
#define maxn (int) (1e5 + 7)
using namespace std;
int n, m, k;
pair<int, int> Range[maxn];
inline pair<int, int> cb(pair<int, int> x, pair<int, int> y) {
return { min(x.first, y.first), max(x.second, y.second) };
}
struct IT {
pair<int, int> st[2 * maxn];
void update(int x, pair<int, int> val) {
int id = x + n;
st[id] = val;
while(id != 1) {
id >>= 1;
st[id] = cb(st[id * 2], st[id * 2 + 1]);
}
}
pair<int, int> get(int l, int r) {
pair<int, int> ans = {n + 1, 0};
l += n, r += n;
while(l <= r) {
ans = cb(ans, st[l]), ans = cb(ans, st[r]);
l = (l + 1) >> 1, r = (r - 1) >> 1;
}
return ans;
}
} St[18];
pair<int, int> dq[maxn];
void prepare() {
int d = 1, c = 0;
fi(i, 1, n) {
while(d <= c && dq[c].first < Range[i].second) -- c;
dq[++c] = {Range[i].second, i};
while(d <= c && dq[d].second < i - k + 1) ++d;
Range[i].second = dq[d].first;
}
d = 1, c = 0;
fid(i, n, 1) {
while(d <= c && dq[c].first > Range[i].first) --c;
dq[++c] = {Range[i].first, i};
while(d <= c && dq[d].second > i + k - 1) ++d;
Range[i].first = dq[d].first;
}
}
int query(int x, int y) {
auto [l, r] = St[17].get(x, x);
if(!(l <= y && y <= r)) return -1;
int ans = 0; l = x, r = x;
fid(i, 17, 0) {
auto [u, v] = St[i].get(l, r);
if(!(u <= y && y <= v)) l = u, r = v, ans += 1 << i;
}
return ans + 1;
}
void solve() {
cin >> n >> k >> m;
fi(i, 1, n) Range[i] = {i, i};
fi(i, 1, m) {
int x, y; cin >> x >> y;
Range[x] = cb(Range[x], {y, y});
}
prepare();
fi(i, 1, n) St[0].update(i, Range[i]);
fi(j, 1, 17) {
fi(i, 1, n) {
auto [l, r] = St[j - 1].get(i, i);
St[j].update(i, St[j - 1].get(l, r));
}
}
int q; cin >> q;
fi(i, 1, q) {
int x, y; cin >> x >> y;
cout << query(x, y) << '\n';
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
if(fopen(name".inp", "r")) {
freopen(name".inp", "r", stdin);
freopen(name".out", "w", stdout);
}
solve();
}
