#include<iostream>
using namespace std;
typedef long long ll;
int main(){
	ll n,k;
	ll all=1;
	cin>>n>>k;
	string password;
	cin>>password;
	// cerr<<"password:"<<password<<endl;
	string a[10010];
	for(int i=1;i<=n;i++){
		int x;
		cin>>x>>a[i];
		all*=x;
		int len=a[i].size();
		int cnt=0;
		for(int j=0;j<len;j++){
			// cerr<<"a["<<i<<"]["<<j<<"]="<<a[i][j]<<endl;
			// cerr<<"password["<<i-1<<"]="<<password[i-1]<<endl;
			if(a[i][j]==password[i-1]){
				cnt++;
			}
		}
		if(cnt==0){
			cout<<-1<<endl;
			return 0;
		}
	}
	string b[10010];
	int k1=k;
	for(int i=1;i<=k;i++){
		cin>>b[i];
		int len=b[i].size();
		int cnt=0;
		for(int l=1;l<=n;l++){
			for(int j=0;j<len;j++){
				//cerr<<"b["<<l<<"]["<<j<<"]="<<b[l][j]<<endl;
				//cerr<<"password["<<l-1<<"]="<<password[l-1]<<endl;
				if(b[l][j]==password[l-1]){
					cnt++;
				}
			}
		}
		if(cnt==0){
			k1--;
		}
	}
	cout<<all-k1<<endl;
	return 0;
}