// #pragma GCC optimize("Ofast,unroll-loops")
// #pragma GCC target("avx2,tune=native")

#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <locale>
#include <map>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <unordered_set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <utility>
#include <valarray>
#include <vector>
#include <cstring>
#include <unordered_map>
#include <cmath>
#include <array>
#include <cassert>
#include <random>
#include <chrono>

using namespace std;

#define          BIT(i,j)  (((i)>>(j))&1LL)
#define           MASK(i)  (1LL<<(i))
#define            ALL(x)  (x).begin(),(x).end()
#define             SZ(x)  (int)(x).size()
#define                fi  first
#define                se  second
#define               ull  ungsigned long long
#define                ll  long long
#define                ld  long double
#define                vi  vector<int>
#define               vvi  vector<vi>
#define              vvvi  vector<vvi>
#define               pii  pair<int,int>
#define              vpii  vector<pii>
#define             vvpii  vector<vpii>
#define REPDIS(i,be,en,j)  for(int i = (be); i<=(en); i+=j)
#define     REPD(i,be,en)  for(int i = (be); i>=(en); i--)
#define      REP(i,be,en)  for(int i = (be); i<=(en); i++)
#define              endl  "\n"
#define                MP  make_pair
#define               int  ll

//-----------------------------------------------------------------------------------------------//
inline void scan(){} template<typename F, typename... R> inline void scan(F &f,R&... r){cin>>f;scan(r...);}
inline void print(){} template<typename F, typename... R> inline void print(F f,R... r){cout<<f;print(r...);}
//-----------------------------------------------------------------------------------------------//

void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
//------------------------------------------------------------------------------------------------//
const  ll   LINF = 1e18;
const int    INF = 1e9;
const int    LOG = 20;
const int   MAXN = 5e5+7;
const int      N = 1e2+3;
const int    MOD = 1e9+7;
const int   BASE = 1e5;
const  ld    EPS = 1e-9;
const  ld     PI = acos(-1);
const int OFFSET = 1e3;
//------------------------------------------------------------------------------------------------//
template<typename T1, typename T2> bool mini(T1 &a, T2 b){if(a>b){a=b;return true;}return false;}
template<typename T1, typename T2> bool maxi(T1 &a, T2 b){if(a<b){a=b;return true;}return false;}
template<typename T> T gcd(T a, T b) { while(b) { a %= b; swap(a,b); } return a; }
template<typename T> T lcm(T a, T b) { return a/gcd(a,b)*b; }
//------------------------------------------------------------------------------------------------//

/*
----------------------------------------------------------------
    END OF TEMPLATE
----------------------------------------------------------------
*/

void add(int &a, int b){
    a += b;
    if(a>=MOD) a -= MOD;
}

int dp[MAXN][27],a[MAXN],s[MAXN];

void solve(){
    int n; cin >> n;
    for(int i = 1; i<=n; i++) cin >> a[i];
    for(int i = 1; i<=n; i++){
        char c; cin >> c;
        s[i] = c-'a';
    }
    dp[0][26] = 1;
    for(int i = 1; i<=n; i++){
        int now = s[i];
        for(int j = 0; j<=26; j++){
            add(dp[i][j],dp[i-1][j]);
            if(j!=now){
                add(dp[i][now],1LL*dp[i-1][j]*a[i]%MOD);
            }
        }
    }
    int res = 0;
    for(int i = 0; i<=25; i++){
        add(res,dp[n][i]);
    }
    cout << res << endl;
}

signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    #define task "test"
    if(fopen(task".inp","r")){
        freopen(task".inp","r",stdin);
        freopen(task".out","w",stdout);
    }
    #define task1 "nothing"
    if(fopen(task1".inp","r")){
        freopen(task1".inp","r",stdin);
        freopen(task1".out","w",stdout);
    }

    int test = 1;

    while(test--){
        solve();
    }
    cerr << "\nTime elapsed: " << 1000*clock()/CLOCKS_PER_SEC << "ms\n";
    return 0;
}

/**  /\_/\
 *  (= ._.)
 *  / >TL \>AC
**/