#include <bits/stdc++.h>
#define fst first
#define snd second
#define pb push_back
#define forn(i,a,b) for(int i = a; i < b; i++)
#define ALL(x) x.begin(),x.end()
#define mset(a,v) memset(a,v,sizeof(a))
using namespace std;
typedef long long ll;
#define NEUT (ll)-1
struct STree{
ll n;
vector<ll> st;
STree(ll n=0):n(n),st(4*n+5,-1){}
void upd(ll k,ll l,ll r, ll p, ll v){
if(l+1==r){ st[k]=v; return; }
ll mid = (l+r)/2;
if(mid>p) upd(2*k,l,mid,p,v);
else upd(2*k+1,mid,r,p,v);
st[k]=max(st[2*k],st[2*k+1]);
}
ll query(ll k,ll l,ll r,ll L,ll R){
if(l>=R||r<=L) return NEUT;
if(l>=L&&r<=R) return st[k];
ll mid = (l+r)/2;
return max(query(2*k,l,mid,L,R),query(2*k+1,mid,r,L,R));
}
void upd(ll p,ll v){ upd(1,0,n,p,v); }
ll query(ll l,ll r){ return query(1,0,n,l,r); }
};
const int MAXN = 200000+5;
const int MAXP = 20;
ll n,k,m;
ll aa[MAXN];
ll bb[MAXN];
ll blift[MAXN][MAXP];
STree st[MAXP];
void precalc(){
vector<pair<ll,ll>> orden={};
forn(i,0,m){
orden.pb({aa[i],bb[i]});
orden.pb({aa[i]+k-1,bb[i]*-1});
}
sort(ALL(orden));
reverse(ALL(orden));
multiset<ll> vals;
queue<ll> era;
forn(i,1,n+1){
while(!orden.empty() && orden.back().fst<=i){
pair<ll,ll> aux = orden.back();
//cout<<aux.fst<<" __ "<<aux.snd<<'\n';
if(aux.snd>0) vals.insert(aux.snd*-1);
else era.push(aux.snd);
orden.pop_back();
}
ll val;
if(vals.empty()) val=i;
else val=abs(*vals.begin());
//cout<<i<<" "<<val<<'\n';
st[0].upd(i,val);
//cout<<st[0].query(i,i+1)<<'\n';
/*cout<<"--\n";
for(auto j:vals) cout<<j<<" "; cout<<'\n';
cout<<"--\n";*/
while(!era.empty()){
val = era.front();
vals.erase(vals.find(val));
era.pop();
}
}
forn(p,1,MAXP){
forn(i,1,n+1){
st[p].upd(i,st[p-1].query(i,st[p-1].query(i,i+1)+1));
//cout<<i<<" "<<p<<" -> "<<st[p].query(i,i+1)<<'\n';
}
}
}
int main(){
cin>>n>>k>>m;
mset(aa,-1); mset(bb,-1);
forn(i,0,m) cin>>aa[i]>>bb[i];
forn(i,0,MAXP){
st[i]=STree(n+5);
}
precalc();
ll q; cin>>q;
while(q--){
ll ini,fin; cin>>ini>>fin;
ll l = ini; ll r = l+1;
ll res = 0;
for(int p = MAXP-1; p>=0; p--){
ll qry = st[p].query(l,r);
if(qry<fin){
r=qry+1;
res+=1<<p;
}
}
if(st[MAXP-1].query(ini,ini+1)<fin) res=-2;
cout<<res+1<<'\n';
}
return 0;
}
