//g++ 1.cpp -std=c++14 -O2 -I .
#include <bits/stdc++.h>
using namespace std;

#include <atcoder/all>
using namespace atcoder;

using ll = long long;
using ld = long double;

using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vld = vector<ld>;
using vvld = vector<vld>;
using vst = vector<string>;
using vvst = vector<vst>;

#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define pq_big(T) priority_queue<T,vector<T>,less<T>>
#define pq_small(T) priority_queue<T,vector<T>,greater<T>>
#define all(a) a.begin(),a.end()
#define rep(i,start,end) for(ll i=start;i<(ll)(end);i++)
#define per(i,start,end) for(ll i=start;i>=(ll)(end);i--)
#define uniq(a) sort(all(a));a.erase(unique(all(a)),a.end())

constexpr ll mod = 1e9+7;

ll op(ll a,ll b){
  return (a+b)%mod;
}
ll e(){
  return 0;
}

segtree<ll,op,e> seg(205000);

int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  seg.set(0,1);

  int n;
  cin>>n;

  vll a(n);
  rep(i,0,n)cin>>a[i];

  string s;
  cin>>s;

  vi prev(26,0);

  rep(i,1,n+1){
    char c=s[i-1];
    int p=prev[c-'a'];

    prev[c-'a']=i;

    ll pr=seg.prod(p,i);
    if(p!=0){
      ll g=seg.get(p);
      pr-=g;
      g*=pow_mod(a[p-1],mod-2,mod);
      g%=mod;
      pr+=g;
    }
    seg.set(i,(pr*a[i-1])%mod);
  }

  ll pr=seg.all_prod();
  pr--;
  pr=(pr%mod+mod)%mod;

  cout<<pr<<endl;
}