#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define _GLIBCXX_DEBUG
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll ILL=1167167167167167167;
const int INF=2100000000;
ll mod=1e9+7;
#define rep(i,a) for (ll i=0;i<a;i++)
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
void yneos(bool a){if(a) cout<<"Yes\n"; else cout<<"No\n";}



//おちこんだりもしたけれど、私はげんきです。
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int N;
	cin>>N;
	ll sum=0;
	vector<ll> p(N);
	rep(i,N){
		cin>>p[i];
		sum+=p[i];
	}
	string T;
	cin>>T;
	assert(sum<=1e7);
	string S;
	rep(i,N){
		rep(j,p[i]) S+=T[i];
	}
	N=S.size();
	int M=26;
	vector<queue<int>> q(M);
	rep(i,N){
		q[(S[i]-'a')].push(i);
	}
	rep(i,M) q[i].push(N+1);
	vector<ll> dp(N+2);
	rep(i,M){
		dp[q[i].front()]=1;
	}
	ll ans=0;
	rep(i,N){
		dp[i]%=mod;
		ans+=dp[i];
		ans%=mod;
		rep(j,M){
			if(q[j].front()==i) q[j].pop();
			dp[q[j].front()]+=dp[i];
		}
	}
	cout<<ans<<"\n";
}