#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;

template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (ll i=(ll)from; i<(ll)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (int i=(int)N-1; i>=0; i--)

const ll MOD = pow(10,9)+7;
const ll LLINF = pow(2,61)-1;
const int INF = pow(2,30)-1;

vector<ll> fac;
void c_fac(int x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; }
ll modpow(ll x, ll p) { ll result = 1, now = 1, pm = x; while (now<=p) { if (p&now) { result = result * pm % MOD; } now*=2; pm = pm*pm % MOD; } return result; }
ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { int d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; }
ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; }
ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }

// ----------------------------------------------------------------------
// ----------------------------------------------------------------------

struct MinCostFlow {
  struct edge { ll to, cap, cost, rev, idx; bool isrev; };
  struct vertex { ll d, from, pos; };
  vector<vector<edge>> adj;
  vector<ll> potential;
  vector<vertex> minlen;

  MinCostFlow(ll n) { adj.resize(n); potential.resize(n); }
  void add_edge(ll from, ll to, ll cap, ll cost, ll idx = -1) {
    adj[from].push_back({to, cap, cost, (ll)adj[to].size(), idx, false});
    adj[to].push_back({from, 0, -1*cost, (ll)adj[from].size()-1, idx, true});
  }
  ll dijkstra(ll from, ll to) {
    ll N = adj.size();
    auto c = [](const p_ll &x, const p_ll &y){return x.second>y.second;};
    priority_queue<p_ll, vector<p_ll>, decltype(c)> q(c);
    minlen.assign(N,{LLINF,-1,-1}); minlen[from] = {0,-1,-1}; q.push(make_pair(from,0));
    while(q.size()) {
      p_ll now = q.top(); q.pop();
      ll np = now.first, nd = now.second;
      if (nd>minlen[np].d) continue;
      for (auto x: adj[np]) {
        if (x.cap==0||minlen[x.to].d<=minlen[np].d+x.cost) continue;
        q.push(make_pair(x.to, minlen[np].d+x.cost));
        minlen[x.to] = {minlen[np].d+x.cost, np, adj[x.to][x.rev].rev};
      }
    }
    return minlen[to].d;
  }
  ll dfs(ll from, ll to, ll flow) {
    if (from==to) return flow;
    auto &e = adj[minlen[to].from][minlen[to].pos];
    ll f = dfs(from, minlen[to].from, min(flow, e.cap));
    e.cap -= f;
    adj[e.to][e.rev].cap += f;
    return f;
  }
  ll calc(ll from, ll to, ll cost) {
    while(true) {
      if (cost==0||dijkstra(from, to)==LLINF) {
        ll result = 0;
        rep(i,adj.size()) {
          for (auto &x: adj[i]) {
            if (!x.isrev) {
              edge rev = adj[x.to][x.rev];
              result += rev.cap * x.cost;
            }
          }
        }
        return cost==0 ? result : LLINF;
      }
      cost -= dfs(from, to, cost);
    }
    return 0;
  }
  void output() {
    rep(i,adj.size()) {
      for (auto &x: adj[i]) {
        if (!x.isrev) {
          edge rev = adj[x.to][x.rev];
          cout << x.idx << ":" << i << "->" << x.to << " " << rev.cap << "/" << x.cap+rev.cap << endl;
        }
      }
    }
  }
};

// ----------------------------------------------------------------------
// ----------------------------------------------------------------------

int main() {
  ll N; cin >> N;
  string S; cin >> S;
  ll V[N]; rep(i,N) cin >> V[i];
  vector<ll> py, pu, pk, pi;
  rep(i,N) {
    if (S[i]=='y') py.push_back(i+1);
    if (S[i]=='u') pu.push_back(i+1);
    if (S[i]=='k') pk.push_back(i+1);
    if (S[i]=='i') pi.push_back(i+1);
  }
  // debug(all(py)); debug(all(pu)); debug(all(pk)); debug(all(pi));

  MinCostFlow mcf(N+2);
  if (!py.size()) { cout << 0 << endl; return 0; }

  mcf.add_edge(0,py[0],INF,0);
  rep(i,py.size()-1) mcf.add_edge(py[i],py[i+1],INF,0);
  rep(i,pu.size()-1) mcf.add_edge(pu[i],pu[i+1],INF,0);
  rep(i,pk.size()-1) mcf.add_edge(pk[i],pk[i+1],INF,0);
  rep(i,pi.size()-1) mcf.add_edge(pi[i],pi[i+1],INF,0);

  for (auto x: py) {
    auto to = lower_bound(all(pu),x);
    if (to!=pu.end()) mcf.add_edge(x,*to,1,INF-V[x-1]);
  }
  for (auto x: pu) {
    auto to = lower_bound(all(pk),x);
    if (to!=pk.end()) mcf.add_edge(x,*to,1,INF-V[x-1]);
  }
  for (auto x: pk) {
    auto to = lower_bound(all(pi),x);
    if (to!=pi.end()) mcf.add_edge(x,*to,1,INF-V[x-1]);
  }
  for (auto x: pi) mcf.add_edge(x,N+1,1,INF-V[x-1]);

  ll result = 0;
  repr(i,1,N+1) {
    ll r = INF*i*4 - mcf.calc(0,N+1,1);
    result = max(result, r);
  }
  cout << result << endl;
  return 0;
}