#include using namespace std; typedef long long ll; typedef pair PP; //#define MOD 1000000007 #define MOD 998244353 #define INF 2305843009213693951 //#define INF 810114514 #define PI 3.141592653589 #define setdouble setprecision #define REP(i,n) for(ll i=0;i<(n);++i) #define OREP(i,n) for(ll i=1;i<=(n);++i) #define RREP(i,n) for(ll i=(n)-1;i>=0;--i) #define ALL(v) (v).begin(), (v).end() #define GOODBYE do { cout << "-1" << endl; return 0; } while (false) #define MM <<" "<< #define Endl endl #define debug true #define debug2 false long long inverse(long long b,long long mod){ /* Copyright (c) 2021 0214sh7 https://github.com/0214sh7/library/ */ long long r=1,e=mod-2; while(e){ if(e&1){ r=(r*b)%mod; } b=(b*b)%mod; e >>=1; } return r; } int main(void){ //cin.tie(nullptr); //ios::sync_with_stdio(false); ll N,M,P,Q; cin >> N >> M >> P >> Q; REP(i,Q){ ll x,f; cin >> x >> f; ll y = (f*inverse(x%P,P))%P; //cout << y << endl; ll Ans = (M+P-y)/P; if(y ==0)Ans--; cout << Ans << endl; } return 0; }