OK спарсы

#include <iostream>
#include <cmath>
#include <vector>
#include <set>
#include <string>
#include <algorithm>
using namespace std;
using ll = long long;
using unt = unsigned int;
void cv(vector <unt> v){
    for (auto x: v) cout<<x<<' ';
    cout<<'\n';
}

vector <unt> level(65);
//степень - массив
unt N=1,M=1,A=1,B=1;
vector <vector <unt> > wrk(15, vector <unt> (25000));
vector <unt> ar(25000);
void make(unt &mx_lvl){
    //cout<<"making wrk\n";
    //for (int i=0;i<N;++i) cout<<wrk[0][i]<<' ';
    //cout<<"\n";
    for (unt i = 1; i <= mx_lvl; ++i){
        unt till = N - level[i];
        //cout<<"N= "<<N<<"\n";
        //cout<<"i= "<<i<<" level[i]= "<<level[i]<<" till= "<<till<<"\n";
        for (unt j = 0; j <= till ; ++j){
            //cout<<"j= "<<j<<"\n";
            unt l = j;
            unt r = j + level[i-1];
            unt L = wrk[i-1][l];
            unt R = wrk[i-1][r];
            //cout<<"lr= "<<l<<" "<<r<<"\n";
            //cout<<"LR= "<<L<<" "<<R<<"\n";
            wrk[i][j] = min(L, R);
            //cout<<"wrk[i][j]= "<<wrk[i][j]<<"\n";
        }
        //for (int h = 0; h <= till;++h) cout<<wrk[i][h]<<' ';
        //cout<<"\n";
    }
}


int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    for (int i = 0;i<65;++i){
        level[i] = pow(2,i);
    }

    while (true){
        cin>>N>>M>>A>>B;
        if (N==0 && M==0 && A==0 && B==0) break;
        unt d;
        unt a,b;
        //cout<<"make sequence\n";
        for (int i = 1;i<=N;++i){
            d = A * i + B;
            //ar.push_back(d);
            ar[i-1] = d;
            wrk[0][i-1]=d;
        }
        unt mx_lvl = log2(N);
        //cout<<"let's make wrk\n";
        make(mx_lvl);
        //cout<<"wrk MADE\n";
        ll ans;
        ll tot = 0;
        /*cout<<"qr:\n";
        for (auto x: qr) cout<<x.first<<' '<<x.second<<'\n';
        cout<<'\n';*/
        //в степень - массив
        /*cout<<"ar\n";
        for (int i=0;i<N;++i) cout<<ar[i]<<' ';
        cout<<"\n";*/
        for (unt i = N+1;i<=N+M*2;++i){
                a = (A * i + B);
                a %= N;
                //a++;
                i++;
                b = (A * i + B);
                b %= N;
                if (a > b) swap(a, b);
                //b++;
                //cout<<"ab= "<<a<<" "<<b<<"\n";
                unt LVL = log2(b-a+1);
                ll lft = wrk[LVL][a];
                ll rgt = wrk[LVL][b - level[LVL] + 1];
                ans = min(lft, rgt);
                //cout<<"ans= "<<ans<<'\n';
                tot += ans;
        }
        cout<<tot<<"\n";
    }
    //cout<<"p= "<<p<<'\n';
}
/*
25000 20000000 1000000000 1000000000
0 0 0 0
*/