#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;
using Modint = atcoder::modint1000000007;

int main(){
    int N;
    cin >> N;
    vector<int> A(N);
    for(int& a : A) cin >> a;
    vector<Modint> dp(26);
    Modint sum = 0;
    for(int i = 0; i < N; i++){
        const Modint x = Modint::raw(A[i]);
        char c;
        cin >> c;
        c -= 'a';
        const Modint diff = (sum - dp[c] + 1) * x;
        dp[c] += diff;
        sum += diff;
    }
    cout << sum.val() << endl;
}