#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<ll,ll> P;
typedef vector<ll> VI;
typedef vector<VI> VVI;
#define REP(i,n) for(int i=0;i<(n);i++)
#define ALL(v) v.begin(),v.end()
template<typename T> bool chmax(T& x, const T& y){return (x<y)?(x=y,true):false;};
template<typename T> bool chmin(T& x, const T& y){return (x>y)?(x=y,true):false;};
constexpr ll MOD=998244353;
constexpr ll INF=2e18;

ll extgcd(ll a, ll b, ll &x, ll &y) {
    if(b==0){
        x=1;
        y=0;
        return a;
    }
    ll gcd=extgcd(b,a%b,x,y);
    ll oldX=x;
    x=y;
    y=oldX-a/b*y;
    return gcd;
}

P crt2(ll b1, ll m1, ll b2, ll m2){
    ll x, y;
    ll d=extgcd(m1,m2,x,y);
    if((b2-b1)%d!=0)
        return {0,-1};
    else{
        ll m=m1*(m2/d);
        return {((b1+((b2-b1)/d)*x%(m2/d)*m1)%m+m)%m,m};
    }
}

int main(){
    ll n, m, p, q;
    cin >> n >> m >> p >> q;
    ll x, f;
    REP(i,q){
        cin >> x >> f;
        P r=crt2(f,p,0,x);
        if(r.first==-1||r.first/x>m)
            cout << 0 << endl;
        else{
            ll k=m-r.first/x;
            cout << k/p+(r.first!=0) << endl;
        }
    }
    return 0;
}