#include<bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using mint=modint1000000007;
using ll=long long;
using pp=pair<int,int>;
#define sr string 
#define vc vector
#define fi first
#define se second
#define rep(i,n) for(int i=0;i<(int)n;i++)
#define pb push_back
#define all(v) v.begin(),v.end()
#define pque priority_queue
#define bpc(a) __builtin_popcount(a)
int main(){
  int n;cin>>n;
  vc<ll>v(n); rep(i,n)cin>>v[i];
  sr s;cin>>s;
  vc<mint>dp(n+1,0); dp[0]=1;
  //vc<mint>dx(n+1,0);
  vc<int>last(26,-1);
  rep(i,n){
    auto&x=dp[i+1];
    x=dp[i]*(v[i]+1);
    int t=last[s[i]-'a'];
    if(t!=-1)x-=(dp[t]-(dp[t]-dp[t-1])/v[t-1])*(v[i]);
    last[s[i]-'a']=i+1;
  }
  mint ans=dp[n]-1;
  cout<<ans.val();
}