#include <stdio.h>
#include <queue>
#include <vector>
#include <string.h>
#include <cassert>
#include <string>
#include <map>

using namespace std;

#define REP(A,B) for(int (A)=0;(A)<(B);(A)++)

char buf[333333];
vector<string> patterns;

struct AhoCorasick {
	enum {alpha=26, first='a'};
	struct Node {
		int back, next[alpha], start=-1, end=-1, nmatches=0;
		Node(int v) { memset(next, v, sizeof(next)); }
	};
	vector<Node> N;
	vector<int> backp;
	void insert(string& s, int j) {
		assert(!s.empty());
		int n = 0;
		for(char c : s) {
			int& m = N[n].next[c-first];
			if(m == -1) { n = m = N.size(); N.emplace_back(-1); }
			else n = m;
		}
		if(N[n].end == -1) N[n].start = j;
		backp.push_back(N[n].end);
		N[n].end = j;
		N[n].nmatches++;
	}
	AhoCorasick(vector<string>& pat) {
		N.emplace_back(-1);
		for(int i = 0; i < pat.size(); i++) {
			insert(pat[i], i);
		}
		N[0].back = N.size();
		N.emplace_back(0);
		queue<int> q;
		for(q.push(0); !q.empty(); q.pop()) {
			int n = q.front(), prev = N[n].back;
			for(int i = 0; i < alpha; i++) {
				int& ed = N[n].next[i], y = N[prev].next[i];
				if(ed == -1) ed = y;
				else {
					N[ed].back = y;
					(N[ed].end == -1 ? N[ed].end : backp[N[ed].start]) = N[y].end;
					N[ed].nmatches += N[y].nmatches;
					q.push(ed);
				}
			}
		}
	}

	vector<int> find(string word) {
		int n = 0;
		vector<int> res;
		for(char c : word) {
			n = N[n].next[c-first];
			res.push_back(N[n].end);
		}
		return res;
	}

	vector< vector<int> > findAll(vector<string>& pat, string word)
	{
		vector<int> r = find(word);
		vector<vector<int>> res(word.size());
		for(int i = 0; i < word.size(); i++) {
			int ind = r[i];
			while(ind != -1) {
				res[i-pat[ind].size()+1].push_back(ind);
				ind = backp[ind];
			}
		}
		return res;
	}
};

char maintext[333333];
int LEN;
int dp[333333];
const int INF = 444444;
vector< int > matches;
/*
int calc(int pos) {
	int& ans = dp[pos];
	if(pos >= LEN) {
		return 0;
	}
	if(ans == -1) {
		if(matches[pos].size() == 0) {
			ans = INF;
			return ans;
		}
		ans = INF;
		for(int x : matches[pos]) {
			ans = min(ans, 1+calc(pos+patterns[x].size()));
		}
	}
	return ans;
}*/

int main()
{
	int L;
	scanf("%d", &L);
	scanf("%s", maintext);
	LEN = strlen(maintext);
	REP(i, L) {
		scanf("%s", buf);
		patterns.push_back(string(buf));		
	}
	AhoCorasick ac(patterns);
	//reverse(maintext, maintext+LEN);
	matches = ac.find(string(maintext));
	REP(i, 333333) dp[i] = INF;
//	REP(i, LEN) printf("%d\n", matches[i]);
	int potrebuju = 0;
	int dosahnu = LEN;
	for(int i = LEN-1; i>= 0; i--) {
		if(matches[i] == -1) {
			if(dosahnu > i) {
				printf("-1\n");
				return 0;
			}
		}
		potrebuju++;

		if(matches[i] != -1) {
			int nejlevejsiIndex = i-patterns[matches[i]].size();
			dosahnu = min(nejlevejsiIndex+1, dosahnu);
		}
	//	printf("i=%d, dosahnu=%d ", i, dosahnu);
		int dal = dosahnu;
		for(int j = i-1; j >= dosahnu; j--) {
//			dp[j] = min(dp[j], dp[i]+1);
			if(matches[j] != -1) {
				int aktualni = j-patterns[matches[j]].size()+1;
				dal = min(dal, aktualni);
//				nejlevejsiIndex = min(aktualni, nejlevejsiIndex);
			}
		}
		i = dosahnu;
		dosahnu = dal;
	//	printf("dal=%d\n", dal);
	}

	if(dosahnu != 0)
		printf("-1\n");
	else
		printf("%d\n", potrebuju);
	return 0;
}