#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 (1000000)
struct SA{
    int sa[MX],R[MX],C[MX],s[MX<<1],t[MX<<1],p[MX],S[MX],U[MX];
    void ss(int n,int m,int*s,int*t,int*p){
        int A=t[n-1]=0,c=*R=-1,*r=s+n,x,y;
        for(int i=n-2;~i;--i)t[i]=s[i]^s[i+1]?s[i]>s[i+1]:t[i+1];
        FOR(i,1,n)R[i]=t[i-1]&&!t[i]?(p[A]=i,A++):-1;
        memset(sa,-1,n*4),memset(S,0,4*m);
        F(n)++S[s[i]];F(m)if(i)S[i]+=S[i-1];F(m)U[i]=S[i]-1;
        for(int i=A-1;~i;--i)sa[U[s[p[i]]]--]=p[i];
        FOR(i,1,m)U[i]=S[i-1];
        F(n)if(sa[i]>0&&t[sa[i]-1])sa[U[s[sa[i]-1]]++]=sa[i]-1;
        F(m)U[i]=S[i]-1;
        for(int i=n-1;~i;--i)if(sa[i]>0&&!t[sa[i]-1])sa[U[s[sa[i]-1]]--]=sa[i]-1;
        F(n)if(~(x=R[sa[i]])){
            if(c<1||p[x+1]-p[x]!=p[y+1]-p[y])++c;
            else for(int j=p[x],k=p[y];j<=p[x+1];++j,++k)
                if((s[j]<<1|t[j])^(s[k]<<1|t[k])){++c;break;}
            r[y=x]=c;
        }
        if(c+1<A)ss(A,c+1,r,t+n,p+A);
        else F(A)sa[r[i]]=i;
        F(A)r[i]=p[sa[i]];
        memset(sa,-1,n*4),memset(S,0,4*m);
        F(n)++S[s[i]];F(m)if(i)S[i]+=S[i-1];F(m)U[i]=S[i]-1;
        for(int i=A-1;~i;--i)sa[U[s[r[i]]]--]=r[i];
        FOR(i,1,m)U[i]=S[i-1];
        F(n)if(sa[i]>0&&t[sa[i]-1])sa[U[s[sa[i]-1]]++]=sa[i]-1;
        F(m)U[i]=S[i]-1;
        for(int i=n-1;~i;--i)if(sa[i]>0&&!t[sa[i]-1])sa[U[s[sa[i]-1]]--]=sa[i]-1;
    }
    void sx(int N,char*r){
        int m,h=*C=0,M=*max_element(r,r+ ++N);
        memset(R,0,4*M+4);
        F(N)R[(int)r[i]]=1;
        F(M)R[i+1]+=R[i];
        F(N)s[i]=R[(int)r[i]]-1;
        m=R[M];
        ss(N,m,s,t,p);
        F(N)R[sa[i]]=i;
        F(N-1){
            while(i+h<N&&sa[R[i]-1]+h<N&&s[i+h]==s[sa[R[i]-1]+h])++h;
            if((C[(int)R[i]-1]=h))--h;
        }
    }
}Z;
char s[MX];
int N,L,M,X[MX],t[MX],c;
vi Q;
int go(){
    int S=0,T=0,l=-1;
    F(N){
        l=max(l,X[i]+i-1);
        if(i==T){
            if(l<T)return -1;
            ++S,T=l+1;
        }
    }
    return S;
}
int main(void){
    scanf("%d%s",&L,s),N=M=strlen(s),s[M++]=63;
    F(L)s[M++]=35,scanf("%s",s+M),M+=t[M]=strlen(s+M);
    Z.sx(M,s);
    F(M+1){
        int I=Z.sa[i];
        if(I<N&&Q.size())X[I]=Q.back();
        if(t[I])Q.PB(t[I]);
        while(!Q.empty()&&Q.back()>Z.C[i])Q.pop_back();
    }
    printf("%d\n",go());
//    F(M+1)printf("%d[%d]: %s\n",i,Z.C[i],s+Z.sa[i]);//TODO ERASE
    return 0;
}