#include<bits/stdc++.h>
using namespace std;
#include <unordered_set>
//#define int long long
#define REP(i,m,n) for(int i=(m);i<(n);i++)
#define rep(i,n) REP(i,0,n)
#define pb push_back
#define all(a) a.begin(),a.end()
#define rall(c) (c).rbegin(),(c).rend()
#define mp make_pair
#define endl '\n'
//#define vec vector<ll>
//#define mat vector<vector<ll> >
#define fi first
#define se second
#define double long double
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> pll;
//typedef long double ld;
typedef complex<double> Complex;
const ll INF=1e9+7;
const ll MOD=998244353;
const ll inf=INF*INF;
const ll mod=INF;
const ll MAX=1000010;
const double PI=acos(-1.0);
typedef vector<vector<ll> > mat;
typedef vector<ll> vec;



void solve(){
    ll n;cin>>n;
    vector<ll>a(n);
    rep(i,n)cin>>a[i];
    string s;cin>>s;
    vector<ll>la(26,-1);
    vector<ll>x(26);
    ll ans=0;
    vector<ll>dp(n+1);
    ll inv2=(mod+1)/2;
    dp[0]=1;
    REP(i,1,n+1){
        ll z=dp[i-1];
        if(la[s[i-1]-'a']>=0)z-=x[s[i-1]-'a'];
        ans=(ans+z*a[i-1]%mod)%mod;
        dp[i]=(dp[i-1]+z*a[i-1]%mod)%mod;
        la[s[i-1]-'a']=i;
        x[s[i-1]-'a']=dp[i]-z;
    }
    ans%=mod;
    if(ans<0)ans+=mod;
    cout<<ans<<endl;
}

signed main(){
    //cin.tie(0);
    //ios::sync_with_stdio(false);
    solve();
}