#line 1 "c.cpp"
#include<bits/stdc++.h>
#include<atcoder/all>
#define rep(i,n) for (int i = 0; i < int(n); ++i)
#define repp(i,n,m) for (int i = m; i < int(n); ++i)
#define reb(i,n) for (int i = int(n)-1; i >= 0; --i)
#define all(v) v.begin(),v.end()
using namespace std;
using namespace atcoder;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using P = pair<int, int>;
using PL = pair<long long, long long>;
using pdd = pair<long double, long double>;
using pil = pair<int,ll>;
using pli = pair<ll,int>;
template<class T>istream &operator>>(istream &is,vector<T> &v){for(auto &e:v)is>>e;return is;}
template<typename T>bool range(T a,T b,T x){return (a<=x&&x<b);}
template<typename T>bool rrange(T a,T b,T c,T d,T x,T y){return (range(a,c,x)&&range(b,d,y));}
template<typename T> T rev(const T& str_or_vec){T res = str_or_vec; reverse(res.begin(),res.end()); return res; }
template<typename T>bool chmin(T &a,const T &b){if(a>b){a=b;return true;}return false;}
template<typename T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<typename T>void uniq(vector<T> &v){sort(v.begin(),v.end());v.erase(unique(v.begin(),v.end()),v.end());}
template<typename T1, typename T2>void print(pair<T1,T2> a);
template<typename T>void print(vector<T> v);
template<typename T>void print(vector<vector<T>> v);
void print(){ putchar(' '); }
void print(bool a){ printf("%d", a); }
void print(int a){ printf("%d", a); }
void print(long a){ printf("%ld", a); }
void print(long long a){ printf("%lld", a); }
void print(char a){ printf("%c", a); }
void print(char a[]){ printf("%s", a); }
void print(const char a[]){ printf("%s", a); }
void print(long double a){ printf("%.15Lf", a); }
void print(const string& a){ for(auto&& i : a) print(i); }
void print(unsigned int a){ printf("%u", a); }
void print(unsigned long long a) { printf("%llu", a); }
template<class T> void print(const T& a){ cout << a; }
int out(){ putchar('\n'); return 0; }
template<class T> int out(const T& t){ print(t); putchar('\n'); return 0; }
template<class Head, class... Tail> int out(const Head& head, const Tail&... tail){ print(head); putchar(' '); out(tail...); return 0; }
template<typename T1,typename T2>void print(pair<T1,T2> a){print(a.first);print(),print(a.second);}
template<typename T>void print(vector<T> v){for(auto ite=v.begin();ite!=v.end();){print(*ite);if(++ite!=v.end())print();}}
template<typename T>void print(vector<vector<T>> v){for(auto ite=v.begin();ite!=v.end();){print(*ite);if(++ite!=v.end())out();}}
void yes(){out("Yes");}
void no (){out("No");}
void yn (bool t){if(t)yes();else no();}
void fast_io(){cin.tie(0); ios::sync_with_stdio(0); cout<<fixed<<setprecision(20);}
void o(){out("!?");}

namespace noya2{

const int INF = 1001001007;
const long long mod1 = 998244353;
const long long mod2 = 1000000007;
const long long inf = 2e18;
const long double pi = 3.14159265358979323;
const long double eps = 1e-7;
const vector<int> dx = {0,1,0,-1,1,1,-1,-1};
const vector<int> dy = {1,0,-1,0,1,-1,-1,1};
const string ALP = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const string alp = "abcdefghijklmnopqrstuvwxyz";
const string NUM = "0123456789";

} // namespace noya2
using namespace noya2;

//using mint = modint998244353;
using mint = modint1000000007;
//using mint = modint;
void out(mint a){out(a.val());}
void out(vector<mint> a){vector<ll> b(a.size()); rep(i,a.size()) b[i] = a[i].val(); out(b);}
void out(vector<vector<mint>> a){for (auto v : a) out(v);}
istream &operator>>(istream &is,vector<mint> &v){for(auto &e:v){ll _x;is>>_x;e=_x;}return is;}

#line 2 "Matrix.hpp"

#line 4 "Matrix.hpp"

namespace noya2{

using namespace std;

template<typename T> struct Matrix{
    int rows;
    int cols;
    vector<vector<T>> m;
    Matrix (int h = 0, int w = 0, T init = T(0)) : m(h,vector<T>(w,init)), rows(h), cols(w){}
    Matrix (vector<vector<T>> _init) : m(_init), rows(_init.size()), cols(_init.at(0).size()){}
    vector<T>& operator[](const int i) const {return m[i];}
    vector<T>& operator[](const int i) {return m[i];}
    Matrix &operator+= (const Matrix &r){
        assert(this->rows == r.rows && this->cols == r.cols);
        for (int i = 0; i < r.rows; ++i){
            for (int j = 0; j < r.cols; ++j){
                m[i][j] += r.m[i][j];
            }
        }
        return *this;
    }
    Matrix &operator-= (const Matrix &r){
        assert(this->rows == r.rows && this->cols == r.cols);
        for (int i = 0; i < r.rows; ++i){
            for (int j = 0; j < r.cols; ++j){
                m[i][j] -= r.m[i][j];
            }
        }
        return *this;
    }
    Matrix &operator*= (const Matrix &r){
        assert(this->cols == r.rows);
        Matrix res(rows, r.cols);
        for (int i = 0; i < rows; ++i){
            for (int j = 0; j < r.cols; ++j){
                for (int k = 0; k < r.rows; ++k){
                    res[i][j] += m[i][k] * r.m[k][j];
                }
            }
        }
        return *this = res;
    }
    Matrix operator+ (const Matrix &r) const {return Matrix(*this) += r;}
    Matrix operator- (const Matrix &r) const {return Matrix(*this) -= r;}
    Matrix operator* (const Matrix &r) const {return Matrix(*this) *= r;}
    bool operator== (const Matrix &r){
        if (rows != r.rows || cols != r.cols) return false;
        for (int i = 0; i < r.rows; ++i){
            for (int j = 0; j < r.cols; ++j){
                if (m[i][j] != r.m[i][j]) return false;
            }
        }
        return true;
    }
    Matrix& operator+=(const T &r){
        for (int i = 0; i < rows; ++i){
            for (int j = 0; j < cols; ++j){
                m[i][j] += r;
            }
        }
        return *this;
    }
    Matrix& operator-=(const T &r){
        for (int i = 0; i < rows; ++i){
            for (int j = 0; j < cols; ++j){
                m[i][j] -= r;
            }
        }
        return *this;
    }
    Matrix& operator*=(const T &r){
        for (int i = 0; i < rows; ++i){
            for (int j = 0; j < cols; ++j){
                m[i][j] *= r;
            }
        }
        return *this;
    }
    Matrix& operator/=(const T &r){
        for (int i = 0; i < rows; ++i){
            for (int j = 0; j < cols; ++j){
                m[i][j] /= r;
            }
        }
        return *this;
    }
    Matrix operator+ (const T &r) const {return Matrix(*this) += r;}
    Matrix operator- (const T &r) const {return Matrix(*this) -= r;}
    Matrix operator* (const T &r) const {return Matrix(*this) *= r;}
    Matrix operator/ (const T &r) const {return Matrix(*this) /= r;}
    Matrix e(){
        assert(this->rows == this->cols);
        Matrix res(this->rows, this->rows);
        for (int i = 0; i < rows; ++i) res[i][i] = 1;
        return res;
    }
    Matrix pow(long long n){
        assert(this->rows == this->cols);
        if (n == 0) return e();
        Matrix f = pow(n / 2);
        Matrix ans = f * f;
        if (n % 2 == 1) ans *= *this;
        return ans;
    }
    // for T = int, long long, double, long double
    void show(){
        for (int i = 0; i < rows; ++i){
            for (int j = 0; j < cols; ++j){
                cout << m[i][j] << (j+1 == this->cols ? "\n" : " ");
            }
        }
    }
};

} // namespace noya2
#line 78 "c.cpp"

void solve(){
    int n; cin >> n;
    vector<ll> a(n); cin >> a;
    string s; cin >> s;
    vector<mint> dp(26,0);
    mint sum = 0;
    vector<vector<int>> ini = {{0,1,1},{-1,2,1},{0,0,1}};
    Matrix<mint> mat(3,3); rep(i,3) rep(j,3) mat[i][j] = ini[i][j];
    rep(i,n){
        Matrix<mint> f(3,1); f[0][0] = dp[s[i]-'a'], f[1][0] = sum, f[2][0] = 1;
        auto g = mat.pow(a[i]) * f;
        dp[s[i]-'a'] = g[0][0];
        sum = g[1][0];
    }
    out(sum);
}

int main(){
    fast_io();
    int t = 1; //cin >> t;
    while(t--) solve();
}