#include <bits/stdc++.h>
using namespace std;
map<char, int> id;
void prepare() {
	for (int i = 'A'; i <= 'Z'; i++) id[i] = i - 'A';
	for (int i = 'a'; i <= 'z'; i++) id[i] = i - 'a' + 26;
}
int k;
constexpr int N = 55 * 55;
int ch[N][2], tot = 1, val[N], fail[N];
vector<int> son[N];
void insert(string str) {
	int now = 1;
	for (char c : str) {
		int &nxt = ch[now][c - '0'];
		if (!nxt) nxt = ++tot;
		now = nxt;
	}
	val[now] = 1;
}
void build() {
	queue<int> q;
	for (int i : {0, 1}) {
		if (!ch[1][i]) {
			ch[1][i] = 1;
		} else {
			fail[ch[1][i]] = 1;
			q.push(ch[1][i]);
		}
	}
	while (!q.empty()) {
		int u = q.front();
		q.pop();
		for (int i : {0, 1}) {
			if (!ch[u][i]) ch[u][i] = ch[fail[u]][i];
			else fail[ch[u][i]] = ch[fail[u]][i], q.push(ch[u][i]);
		}
	}
	for (int i = 2; i <= tot; i++) {
		son[fail[i]].push_back(i);
	}
}
void dfs(int u) {
	for (int v : son[u]) {
		val[v] |= val[u];
		dfs(v);
	}
}
int main() {
	prepare();
	cin >> k;
	string s;
	cin >> s;
	vector<string> dict(k);
	int c0 = 0, c1 = 0;
	for (auto &str : dict) {
		cin >> str;
		c0 += str == "0";
		c1 += str == "1";
	}
	if (c0 && c1) {
		cout << -1 << "\n";
		return 0;
	}
	if (!c0 && !c1) {
		int sum = 0;
		for (char c : s) {
			sum += dict[id[c]].size();
		}
		cout << sum << "\n";
		return 0;
	}
	if (!c0) {
		for (auto &str : dict) {
			for (auto &c : str) {
				c ^= 1;
			}
		}
	}
	for (auto str : dict) {
		reverse(str.begin(), str.end());
		insert(str);
	}
	build();
	dfs(1);
	string sb;
	for (char i : s) {
		sb.insert(sb.end(), dict[id[i]].begin(), dict[id[i]].end());
	}
	int now = 1;
	for (int i = sb.size() - 1; i >= 0; i--) {
		now = ch[now][sb[i] - '0'];
		if (!val[now]) {
			cout << count(sb.begin(), sb.begin() + i, '1') + 1 << "\n";
			return 0;
		}
	}
	cout << -1 << "\n";
	return 0;
}