#include <bits/stdc++.h>
using namespace std;
typedef int64_t ll; typedef pair<int, int> pii;
#define pb emplace_back
#define AI(x) begin(x),end(x)
#define ff first
#define ss second
#ifdef OWO
#define debug(args...) LKJ("\033[0;32m[ " + string(#args) + " ]\033[0m", args)
template<class I> void LKJ(I&&x) { cerr << x << endl; }
template<class I, class...T> void LKJ(I&&x, T&&...t) { cerr << x << ", "; LKJ(t...); }
template<class I> void OI(I a, I b) { while (a != b) cerr << *a << ' ', ++a; cerr << endl; }
#else
#define debug(...) 0
#define OI(...) 0
#endif
struct RMQ {
int n; vector<int> val;
RMQ() = default;
void build(int i, int l, int r, const vector<int>& v) {
if (l == r) {
val[i] = v[l];
return;
}
int m = (l + r) / 2;
build(i * 2, l, m, v);
build(i * 2 + 1, m + 1, r, v);
val[i] = max(val[i * 2], val[i * 2 + 1]);
}
void build(const vector<int>& v) {
n = v.size();
val.resize(n * 4);
build(1, 1, n, v);
}
int query(int i, int l, int r, int ql, int qr) {
if (ql <= l and r <= qr) return val[i];
int m = (l + r) / 2;
int ans = 0;
if (ql <= m) ans = max(ans, query(i * 2, l, m, ql, qr));
if (m < qr) ans = max(ans, query(i * 2 + 1, m + 1, r, ql, qr));
return ans;
}
int query(int l, int r) {
return query(1, 1, n, l, r);
}
};
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int N, K; cin >> N >> K;
int M; cin >> M;
vector<int> A(M + 1), B(M + 1);
for (int i = 1; i <= M; ++i)
cin >> A[i] >> B[i];
int Q; cin >> Q;
vector<int> S(Q + 1), T(Q + 1);
for (int i = 1; i <= Q; ++i)
cin >> S[i] >> T[i];
vector<vector<int>> ono(N + 1);
for (int i = 1; i <= M; ++i) {
assert(A[i] < B[i]);
ono[A[i]].pb(B[i]);
if (A[i] + K <= N)
ono[A[i] + K].pb(-B[i]);
}
multiset<int> st;
vector<int> rightmost(N + 1, 0);
for (int i = 1; i <= N; ++i) {
for (const int& v: ono[i]) {
if (v > 0) st.insert(v);
else {
auto it = st.find(-v);
st.erase(it);
}
}
if (!st.empty())
rightmost[i] = max(i, *rbegin(st));
else
rightmost[i] = i;
}
int lg = __lg(N) + 1;
RMQ rmq;
vector<vector<int>> jmp(lg + 1, vector<int>(N + 1, 0));
jmp[0] = rightmost;
for (int l = 1; l <= lg; ++l) {
rmq.build(jmp[l - 1]);
for (int i = 1; i <= N; ++i) {
int rb = jmp[l - 1][i];
jmp[l][i] = rmq.query(i, rb);
}
debug(l);
OI(AI(jmp[l]));
}
for (int i = 1; i <= Q; ++i) {
int s = S[i], t = T[i];
if (jmp[lg][s] < t) {
cout << -1 << '\n';
continue;
}
int ans = 0;
for (int l = lg; l >= 0; --l)
if (jmp[l][s] < t) {
ans += (1 << l);
s = jmp[l][s];
}
cout << ans + 1 << '\n';
}
return 0;
}
