#include<bits/stdc++.h>
using namespace std;
using ll=long long;

long long modinv(long long a, long long m) {
    long long b = m, u = 1, v = 0;
    while (b) {
        long long t = a / b;
        a -= t * b; swap(a, b);
        u -= t * v; swap(u, v);
    }
    u %= m;
    if (u < 0) u += m;
    return u;
}

int main(){
  ll n,m,p,q;
  cin>>n>>m>>p>>q;
  while(q--){
    ll x,f;
    cin>>x>>f;
    ll inv=modinv(x,p);
    ll y=f*inv%p;
    ll cnt=(m-y)/p;
    if(y<=m){
      cnt++;
    }
    if(y==0){
      cnt--;
    }
    cout<<cnt<<endl;
  }
}