#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0; i<n; i++)
#define Sort(vector) sort(vector.begin(), vector.end())
#define Reverse(vector) reverse(vector.begin(), vector.end())
#define RSort(vector) sort(vector.rbegin(), vector.rend())
using ll = long long;
using P = pair<int,int>;
using TU = tuple<int,int,int>;
using vint = vector<int>;
using vvint = vector<vint>;
using vvvint = vector<vvint>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
template<typename T> istream &operator>>(istream &is,vector<T> &v){for(T &in:v){is>>in;}return is;}
template<typename T> ostream &operator<<(ostream &os,vector<T> &v){for(int i=0;i<(int)v.size();i++){os<<v[i]<<" \n"[i==(int)v.size()-1];}return os;}
template<typename T> istream &operator>>(istream &is,vector<vector<T>> &v){for(vector<T> &in:v){is>>in;}return is;}
template<typename T> ostream &operator<<(ostream &os,vector<vector<T>> &v){for(vector<T> &out:v){os<<out;}return os;}

// 制約: nとmodが互いに素
ll modinv(ll n,ll mod){
  ll b=mod,u=1,v=0;
  while(b){
    ll t=n/b;
    n-=t*b; swap(n,b);
    u-=t*v; swap(u,v);
  }
  u%=mod;
  if(u<0) u+=mod;
  return u;
}


int main(){
  ll n,m,p,q;cin>>n>>m>>p>>q;

  rep(_,q){
    ll x,f;cin>>x>>f;
    x%=p;

    ll val=f*modinv(x,p);
    val%=p;

    // y mod p == val
    int res=m/p;
    if(val && val<=m%p) res++;

    cout<< res <<'\n';
  } 

  return 0;
}