#include <bits/stdc++.h>
using namespace std;
#define PB push_back
#define ZERO (1e-10)
#define INF int(1e9+1)
#define CL(A,I) (memset(A,I,sizeof(A)))
#define DEB printf("DEB!\n");
#define D(X) cout<<"  "<<#X": "<<X<<endl;
#define EQ(A,B) (A+ZERO>B&&A-ZERO<B)
typedef long long ll;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef pair<int,int> ii;
typedef vector<ii> vii;
#define IN(n) int n;scanf("%d",&n);
#define FOR(i, m, n) for (int i(m); i < n; i++)
#define F(n) FOR(i,0,n)
#define FF(n) FOR(j,0,n)
#define FT(m, n) FOR(k, m, n)
#define aa first
#define bb second
void ga(int N,int *A){F(N)scanf("%d",A+i);}
#define MX (300001)
char s[MX],r[MX];
int N,L,X[MX],l;
bool cp(char*s,char*r,int L){
    F(L)if(s[i]^r[i])return 0;
    return 1;
}
int go(){
    int S=0,l=-1,T=0;
    F(N){
        l=max(l,i+X[i]-1);
        if(i==T){
            if(l<i)return -1;
            ++S,T=l+1;
        }
    }
    return S;
}
int main(void){
    scanf("%d%s",&L,s),N=strlen(s);
    F(L){
        scanf("%s",r),l=strlen(r);
        FF(N-l+1)if(X[j]<l&&cp(s+j,r,l))X[j]=l;
    }
    printf("%d\n",go());
    return 0;
}