#include <iostream>
#include <vector>
#include <algorithm>
#define ll long long
using namespace std;
struct Bus {
ll start, speed, arrive;
};
ll l, n, x, m;
vector<ll> s;
vector<Bus> a;
bool srt(Bus a, Bus b) {
return a.start < b.start;
}
void init(int el, int en, vector<ll> t, vector<int> w, int ex, int em, vector<int> es) {
l = el, n = en, x = ex, m = em;
a = vector<Bus>(n), s = vector<ll>(m);
for(int i = 0; i < m; i++) s[i] = es[i];
for(ll i = 0; i < n; i++) {
a[i].start = t[i];
a[i].speed = w[i];
}
sort(a.begin(), a.end(), srt);
for(ll i = 0; i < n; i++) {
a[i].arrive = max(a[i].start+a[i].speed*l, (i == 0 ? 0 : a[i-1].arrive));
//cout << a[i].start << " " << a[i].speed << " " << a[i].arrive << "\n";
}
}
ll arrival_time(ll y) {
ll le = 0, ri = n, mid, ans = n;
while(le<=ri) {
mid = (le+ri)/2;
if(a[mid].start > y) {
ans = mid;
ri = mid-1;
} else le = mid+1;
}
//cout << ans << " " << y+x*l << " " << x << " " << l << " " << (ans == 0 ? 0 : a[ans-1].arrive) << "\n";
return max(y+x*l, (ans == 0 ? 0 : a[ans-1].arrive));
}
