#include <bits/stdc++.h> 

using namespace std;

typedef long long ll;

const int N = (int)1e6 + 12;

const ll inf = (ll)1e18;


ll b, p, d, n, a[N], dp[N], t[N];
ll get(ll l, ll r) {
    return r / p - max(0ll, (l - 1)) / p;
}
ll col[N];
void test() {
    cin >> b >> p >> d >> n;
    for(int i = 1; i <= n; i++) {
        cin >> a[i];
        col[a[i] % p]++;
    }
    ll all = get(0, b) * d, res = all + b;
    for(int i  = 1; i <= p; i++) {
        res = min(res, (get(0, b) - col[p - i]) * d + i + b);
    }
    cout << res << '\n';
}


int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int t = 1;
    // cin >> t;

    while(t--) 
        test();

    return 0;
}