#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	ll n, m, x, d;
	cin >> n;
	vector<string> s(n);
	for (int i = 0; i < n; i++) cin >> s[i];
	cin >> m >> x >> d;
	map<P, int> memo;
	long long ans = 0;
	for (int k = 0; k < m; k++) {
		int i = x / (n - 1);
		int j = x % (n - 1);
		if (i > j) swap(j, i);
		else j++;
		int lmin = min(s[i].length(), s[j].length());
		int tmp = lmin;
		for (int h = 0; h < lmin; h++) {
			if (s[i][h] != s[j][h]) {
				tmp = h;
				break;
			}
		}
		ans += tmp;
		x = (x + d) % (n * (n - 1));
	}
	cout << ans << endl;
	return 0;
}