#include using namespace std; #define rep(i,n) for(ll i=0;i=0;i--) #define perl(i,r,l) for(ll i=r-1;i>=l;i--) #define fi first #define se second #define pb push_back #define ins insert #define pqueue(x) priority_queue,greater> #define all(x) (x).begin(),(x).end() #define CST(x) cout<> #define rev(x) reverse(x); using ll=long long; using vl=vector; using vvl=vector>; using pl=pair; using vpl=vector; using vvpl=vector; const ll MOD=1000000007; const ll MOD9=998244353; const int inf=1e9+10; const ll INF=4e17; const ll dy[9]={0,1,-1,0,1,1,-1,-1,0}; const ll dx[9]={1,0,0,-1,1,-1,1,-1,0}; template inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; } template inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; } struct UnionFind { vector par; vector edge; UnionFind(int n) : par(n, -1),edge(n, 0) {} int root(int x) { if (par[x] < 0) return x; else return par[x] = root(par[x]); } bool same(int x, int y) { return root(x) == root(y); } bool merge(int x, int y) { x = root(x); y = root(y); if (x == y) { edge[x]++; return false; } if (par[x] > par[y]) swap(x, y); par[x] += par[y]; par[y] = x; edge[x] += edge[y]+1; return true; } int size(int x) { return -par[root(x)]; } }; const int mod = 1000000007; const int max_n = 200005; struct mint { ll x; // typedef long long ll; mint(ll x=0):x((x%mod+mod)%mod){} mint operator-() const { return mint(-x);} mint& operator+=(const mint a) { if ((x += a.x) >= mod) x -= mod; return *this; } mint& operator-=(const mint a) { if ((x += mod-a.x) >= mod) x -= mod; return *this; } mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this;} mint operator+(const mint a) const { return mint(*this) += a;} mint operator-(const mint a) const { return mint(*this) -= a;} mint operator*(const mint a) const { return mint(*this) *= a;} mint pow(ll t) const { if (!t) return 1; mint a = pow(t>>1); a *= a; if (t&1) a *= *this; return a; } bool operator==(const mint &p) const { return x == p.x; } bool operator!=(const mint &p) const { return x != p.x; } // for prime mod mint inv() const { return pow(mod-2);} mint& operator/=(const mint a) { return *this *= a.inv();} mint operator/(const mint a) const { return mint(*this) /= a;} }; istream& operator>>(istream& is, mint& a) { return is >> a.x;} ostream& operator<<(ostream& os, const mint& a) { return os << a.x;} using vm=vector; using vvm=vector; struct combination { vector fact, ifact; combination(int n):fact(n+1),ifact(n+1) { assert(n < mod); fact[0] = 1; for (int i = 1; i <= n; ++i) fact[i] = fact[i-1]*i; ifact[n] = fact[n].inv(); for (int i = n; i >= 1; --i) ifact[i-1] = ifact[i]*i; } mint operator()(int n, int k) { if (k < 0 || k > n) return 0; return fact[n]*ifact[k]*ifact[n-k]; } }comb(max_n); int main(){ ll n;cin >> n; vl v(n);rep(i,n)cin >> v[i]; string s;cin >> s; vvl next(n+1,vl(26,n)); per(i,n){ rep(j,26)next[i][j]=next[i+1][j]; next[i][s[i]-'a']=i; } /*rep(i,n+1){ rep(j,3)cout << next[i][j] <<" "; cout << endl; }*/ mint dp[n+1][27];//どこを見てるか、最後にとったものは何か、maxまで取ったか? rep(i,n+1)rep(j,27)dp[i][j]=0; dp[0][26]=1; rep(i,n){ rep(j,26){ rep(to,26){ if(next[i][to]!=n){ if(j!=to)dp[next[i][to]+1][to]+=dp[i][j]*(v[next[i][to]]-1); if(j!=to)dp[next[i][to]+1][26]+=dp[i][j]; } } } rep(to,26){ if(next[i][to]!=n){ dp[next[i][to]+1][to]+=dp[i][26]*(v[next[i][to]]-1); dp[next[i][to]+1][26]+=dp[i][26]; } } } mint ans=0; rep(k,n+1)rep(i,27)ans+=dp[k][i]; cout << ans-1 << endl; }