#include<bits/stdc++.h>
using namespace std;

#define PII pair<int, int>
#define VI vector<int>
#define VPII vector<PII>
#define LL long long
#define f first
#define s second
#define MP make_pair
#define PB push_back
#define LD long double
#define endl '\n'
#define ALL(c) (c).begin(), (c).end()
#define SIZ(c) (int)(c).size()
#define REP(i, n) for (int i = 0; i < (int)(n); i++)
#define FOR(i, b, e) for (int i = (b); i <= (int)(e); i++)
#define FORD(i, b, e) for (int i = (b); i >= (int)(e); i--)
#define ll LL
#define mp MP
#define pb PB
#define st f
#define nd s
#define eb emplace_back
const int inf = 1e9 + 7;
const LL INF = 1e18L + 7;

#define sim template<class n
sim, class s> ostream & operator << (ostream &p, pair<n, s> x)
{return p << "<" << x.f << ", " << x.s << ">";}
sim> auto operator << (ostream &p, n y) ->
typename enable_if<!is_same<n, string>::value, decltype(y.begin(), p)>::type
{int o = 0; for (auto c : y) {if (o++) p << ", "; p << c;} return p << "}";}
void dor() {cerr << endl;}
sim, class...s> void dor(n p, s...y) {cerr << p << " "; dor(y...);}
sim, class s> void mini(n &p, s y) {if (p > y) p = y;}
sim, class s> void maxi(n &p, s y) {if (p < y) p = y;}

#ifdef DEB
#define debug(...) dor(__FUNCTION__, ":", __LINE__, ": ", __VA_ARGS__)
#else
#define debug(...)
#endif

#define I(x) #x " =", (x), " "
#define A(a, i) #a "[" #i " =", i, "] =", a[i], " "

const int MXN = 3e5+5;
char buf[MXN];
char buf2[MXN];
int len[MXN];
LL h_i[MXN];
string in[MXN];

LL pot[MXN];
LL mod = 10000000000000861;
int p = 193;
LL h[MXN];
LL mul(LL a, LL b)
	{
	LL q = (LL)((LD)a * (LD)b / (LD)mod);
	LL r = a * b - q*mod;
	r %= mod;
//	if(r < 0)r += mod; // TODO: uwaga
	return r;
	}

LL get_h(LL a, LL b)
	{
	LL x = (h[b] - mul(h[a-1], pot[b-a+1]))% mod;
	if(x < 0)x += mod;
	return x;
	}

int min_poc[MXN];
const int MAGIC = 200;
int m;
void go_long(LL h, int len)
	{
	FOR(i, len, m)
		{
		if(get_h(i-len+1, i) == h)
			{
			mini(min_poc[i], i-len+1);
			}
		}
	
	}

set<LL> S[MAGIC+1];

int dp[MXN];
const int BASE = 1<<19;
int t[BASE*2];
void insert(int i, int x)
	{
	i += BASE;
	t[i] = x;
	i/=2;
	while(i)
		{
		t[i] = min(t[i*2], t[i*2+1]);
		i/=2;
		}
	}
int query(int a, int b)
	{
	a += BASE-1;
	b += BASE+1;
	int r = 1e9;
	while(a/2 != b/2)
		{
		if(a % 2 == 0)mini(r, t[a+1]);
		if(b % 2 == 1)mini(r, t[b-1]);
		a /= 2;
		b /= 2;
		}
	return r;
	}

int main()
{
	int n;
	scanf("%d", &n);
	scanf(" %s", buf+1);
	m = strlen(buf+1);
	FOR(i, 1, m)min_poc[i] = 1e9;
	
	pot[0] = 1;
	FOR(i, 1, m)
		{
		h[i] = (h[i-1] * p + buf[i]) % mod;
		pot[i] = pot[i-1] * p % mod;
		}
	
	
	REP(i, n)
		{
		scanf("%s", buf2);
		int k = strlen(buf2);
		LL h = 0;
		REP(j, k)
			{
			h = (h * p + buf2[j]) % mod;
			}
//		len2[i] = k;
//		h_i[i] = h;
		
		
		if(k >= MAGIC)
			{
			go_long(h, k);
			}
		else
			{
			S[k].insert(h);
			}
		}
	
	dp[0] = 0;
	FOR(i, 1, m)
		dp[i] = 1e9;
	
	FOR(i, 0, m)
		insert(i, dp[i]);
	
	FOR(i, 1, m)
		{
		if(min_poc[i] > 1e8)
		FOR(j, max(1, i-MAGIC), i)
			{
			int l = i - j + 1;
			if(S[l].size() == 0)continue;
			LL h = get_h(j, i);
			if(S[l].count(h))
				{
				mini(min_poc[i], j);
				break;
				}
			
			}
		
		if(min_poc[i] <= i)
			{
			int x = query(min_poc[i]-1, i) + 1;
			dp[i] = x;
			insert(i, x);
			}
		}
	if(dp[m] > 1e8)
		{
		puts("-1");
		}
	else
		{
		cout << dp[m] << endl;
		}	
}