#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a; i<b; i++)
#define mp make_pair
#define pb push_back
#define mitte (lewy+prawy)/2
#define fi first
#define se second
#define debug //

typedef long long ll;
typedef pair<int, int> pii;
const int alfa=28;
vector <int> rob, tree;
vector <vector <int> > graf;
vector <int> znak, up, dlu, tab, vat;
vector <int> dp;
vector <pii> kol;
string note;
int n, m;
int x;
void add (string &s, int pos=0, int a=0)
{
	if (pos==(int)s.size()) 
	{
		dlu[a]=max(dlu[a], pos);
		return;
	}
	if (graf[a][s[pos]-'a']==-1)
	{
		dlu.pb(0);
		vat.pb(a);
		znak.pb(s[pos]-'a');
		kol.pb(mp(pos,x));
		graf[a][s[pos]-'a']=x++;
		graf.pb(rob);
		
		
		debug ("new node %d\n", x-1);
		//cerr <<s <<"\n";
	}
	add(s,pos+1, graf[a][s[pos]-'a']);
}
int suf (int c, int a)
{
	debug ("suf %d %d\n", c, a);
	if (graf[a][c]!=-1)
	{
		return graf[a][c];
	}
	if (a==0) return 0;
	return suf(c,up[a]);
}
void walk (int a=0, int pos=0)
{
	debug ("walk %d %d\n", a, pos);
	if (pos==(int)note.size()) return;
	if (graf[a][note[pos]-'a']==-1)
	{
		if (a>0) walk(up[a], pos);
		else walk(a,pos+1);
		return;
	}
	else
	{
		tab[pos]=dlu[graf[a][note[pos]-'a']];
		walk(graf[a][note[pos]-'a'], pos+1);
	}
}
void ustaw (int x, int y, int a=1, int lewy=0, int prawy=m-1)
{
	if (lewy<prawy)
	{
		if (x<=mitte) ustaw(x,y,a*2,lewy,mitte);
		else ustaw(x,y,a*2+1,mitte+1, prawy);
		tree[a]=min(tree[a*2], tree[a*2+1]);
	}
	else tree[a]=y;
}
int mini (int left, int right, int a=1, int lewy=0, int prawy=m-1)
{
	debug ("mini %d %d: %d [%d %d]\n", left, right, a*2, lewy,prawy);
	if (left<=lewy && right>=prawy) return tree[a];
	else
	{
		int ret=1e9;
		if (left<=mitte) ret=min(ret, mini(left, right, a*2, lewy, mitte));
		if (right>mitte) ret=min(ret, mini(left, right, a*2+1, mitte+1, prawy));
		return ret;
	}
}
int main()
{
	ios_base::sync_with_stdio(false);
	x=1;
	rob.resize(alfa,-1);
	dlu.pb(0);
	vat.pb(0);
	znak.pb(-1);
	graf.pb(rob);
	cin>>n >>note;
	m=note.size();
	string s;
	rep(i,0,n)
	{
		cin>>s;
		add(s);
	}
	sort(kol.begin(), kol.end());
	up.resize(x,0);
	for (pair <int, int>  k: kol) 
	{
		if (vat[k.se]==up[k.se]) continue;
		up[k.se]=suf(znak[k.se], up[vat[k.se]]);
		dlu[k.se]=max(dlu[k.se], dlu[up[k.se]]);
		debug ("%d %d\n", k.se, up[k.se]);
	}
	debug ("aho gotowe\n");
	//return 0;
	tab.resize(m,0);
	dp.resize(m,1e9);
	walk();
	
	//teraz drzewo:
	tree.resize(m*4+10,1e9);
	rep(i,0,m)
	{
		debug ("%d\n", i);
		if (tab[i]==i+1) dp[i]=1;
		else
		{
			dp[i]=mini(i-tab[i], i)+1;
		}
		ustaw(i, dp[i]);
		debug ("do %d: %d\n", i, dp[i]);
	}
	if (dp[m-1]==1e9) cout<<"-1\n";
	else cout<<dp[m-1] <<"\n";
	return 0;
}