#include<bits/stdc++.h>
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) (int) (x).size()
#define pb push_back
#define fi first
#define se second

using namespace std;

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef long double LD;

struct aho
{
	struct out_node
	{
			string keyword;
			out_node * next;
			out_node(string k, out_node * n) : keyword(k), next(n){}
	};
	
	struct go_node{
		map<char, go_node * > next;
		out_node * out;
		go_node * fail;
		go_node() {out = NULL; fail = NULL; } } ;
	go_node * go;
	aho(vector<string> keywords)
	{
		go = new go_node();
		for(auto & k: keywords)
		{
			go_node * cur = go;
			for(auto & c : k)	
				cur = cur->next.find(c) != cur->next.end() ? cur->next[c] : (cur->next[c] = new go_node());
			cur->out = new out_node(k, cur->out);
		}
		queue<go_node *> q;
		for(auto & a : go->next)
			q.push(a.second);
		while(SZ(q))
		{
			go_node * r = q.front();
			q.pop();
			for(auto & a : r->next)
			{
				go_node * s = a.second;
				q.push(s);
				go_node * st = r->fail;
				while(st && st->next.find(a.first) == st->next.end())
					st = st->fail;
				if(!st) st = go;
				s->fail = st->next[a.first];
				if(s->fail)
				{
						if(!s->out) s->out = s->fail->out;
						else
						{
							out_node * out = s->out;
							while(out->next) out = out->next;
							out->next = s->fail->out;
						} 
				}  	
			} 
		}
	}
	
	vector<int> rob(string s)
	{
		go_node * cur = go;
		int mom = 0;
		vector<int> res;
		for(auto & c: s)
		{
			mom++;
			while(cur && cur->next.find(c) == cur->next.end())
				cur = cur->fail;
			if(!cur) cur = go;
			cur = cur->next[c];
			if(!cur)
				cur = go;
			for(out_node * out = cur->out;out;out = out->next)
			{
				res.push_back(mom);
				break;
			}
			
		}
		return res;
	}
};

map<int, vector<string> > mapa;

const int inf = 1e9 + 7;

const int maxn = 1e6 + 7;

int gdzie[maxn];

const int pot = 1<<20;

int tree[2 * pot + 7];

void add(int l, int p, int val)
{
	l += pot;
	p += pot;
	while(l <= p)
	{
		if(l & 1)
			tree[l] = min(tree[l], val);
		if(!(p & 1))
			tree[p] = min(tree[p], val);
		l = (l + 1) / 2;
		p = (p - 1) / 2;
	}
}

int val(int x)
{
	x += pot;
	int res = inf;
	while(x > 0)
	{
		res = min(res, tree[x]);
		x /= 2;
	}
	return res;
}

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	for(int i = 0 ;i < 2 * pot;i++)
		tree[i] = inf;
	int n;
	cin>>n;
	string wzo;
	cin>>wzo;
	for(int i = 1;i <= n;i++)
	{
		string a;
		cin>>a;
		mapa[SZ(a)].pb(a);
	}
	
	for(int i = 1;i <= SZ(wzo);i++)
		if(SZ(mapa[i]))
		{
			aho cnt(mapa[i]);
			auto xd = cnt.rob(wzo);
			for(auto s : xd)
				gdzie[s - i + 1] = max(gdzie[s - i + 1], s + 1);
		}
	//for(int i = 1;i <= SZ(wzo);i++)
	//	cerr<<i<<" "<<gdzie[i]<<endl;
	add(1, gdzie[1], 1);
	for(int i = 2;i <= SZ(wzo);i++)
		add(i, gdzie[i], val(i) + 1);
	int res = val(SZ(wzo) + 1);
	if(res > SZ(wzo) * 2)
		cout<<-1;
	else
		cout<<res;
	return 0;
}