#include <bits/stdc++.h>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;
typedef unsigned long long ull;

class Dinic {
  int MAX_V;
  int INF;
  struct edge{ int to, cap, rev, icap, flow; };

  vector< vector<edge> > G;
  vector<int> level; //sからの距離
  vector<int> iter; //どこまで調べたか

  void max_flow_bfs(int s){
    fill(level.begin(), level.end(), -1);
    queue<int> que;
    level[s] = 0;
    que.push(s);
    while(!que.empty()){
      int v = que.front(); que.pop();
      for(int i=0; i<G[v].size(); i++){
        edge &e = G[v][i];
        if(e.cap>0 && level[e.to]<0){
          level[e.to] = level[v] + 1;
          que.push(e.to);
        }
      }
    }
  }
  int max_flow_dfs(int v, int t, int f){
    if(v==t) return f;
    for(int &i=iter[v]; i<G[v].size(); i++){
      edge &e = G[v][i];
      if(e.cap>0 && level[v]<level[e.to]){
        int d = max_flow_dfs(e.to, t, min(f, e.cap));
        if(d>0){
          e.cap -= d;
          G[e.to][e.rev].cap += d;
          e.flow += d;
          return d;
        }
      }
    }
    return 0;
  }

public:
  Dinic(int N):MAX_V(N),G(N),level(N),iter(N){
    INF = 99999999;
  }

  void add_edge(int from, int to, int cap){
    G[from].push_back((edge){to, cap, (int)G[to].size(), cap, 0});
    G[to].push_back((edge){from, 0, (int)G[from].size()-1, 0, 0});
  }

  int get_flow(int from, int to){ //untried
    rep(i,G[from].size()){
      if(G[from][i].to == to){
        return G[from][i].flow;
      }
    }
    return -1;
  }

  int max_flow(int s, int t){
    int flow = 0;
    while(true){
      max_flow_bfs(s);
      if(level[t]<0) return flow;
      fill(iter.begin(), iter.end(), 0);
      int f;
      while((f = max_flow_dfs(s, t, INF))>0){
        flow += f;
      }
    }
  }

  int min_cut(int s, int t, vector<int>& S, vector<int>& T){
    S.clear();
    T.clear();

    int maxf = max_flow(s, t);
    for(int i=0; i<level.size(); i++){
      if(level[i] >= 0) S.push_back(i);
      else T.push_back(i);
    }

    return maxf;
  }
};



class CostScalingMinCostFlow {
  static constexpr double alpha = 2;

 public:
  struct Node {
    int b;
    double p;
    int in_f, out_f;
    Node() : b(0), p(0), in_f(0), out_f(0) {}
    Node(int b, double p) : b(b), p(p), in_f(0), out_f(0) {}
  };

  struct Edge {
    int from, to;
    int cap, cost;
    int rev;
    int f;
    bool isrev;
    Edge() : from(-1), to(-1), cap(0), cost(0), rev(-1), f(0), isrev(false) {}
    Edge(int from, int to, int cap, int cost, int rev, int f, bool isrev)
        : from(from),
          to(to),
          cap(cap),
          cost(cost),
          rev(rev),
          f(f),
          isrev(isrev) {}
  };

 private:
  std::vector<Node> nodes;
  std::vector<std::vector<Edge>> G;
  double epsilon;
  std::queue<int> active_nodes;

  int residual_cap(const Edge& e) const {
    if (!e.isrev)
      return e.cap - e.f;
    else
      return G[e.to][e.rev].f;
  }

  double reduced_cost(const Edge& e) const {
    return e.cost + nodes[e.from].p - nodes[e.to].p;
  }
  int excess(int i) const {
    return nodes[i].b - nodes[i].out_f + nodes[i].in_f;
  }
  bool is_active(int i) const { return excess(i) > 0; }

  void push(Edge& edge, int delta) {
    if (!edge.isrev) {
      edge.f += delta;
      nodes[edge.from].out_f += delta;
      nodes[edge.to].in_f += delta;
    } else {
      G[edge.to][edge.rev].f -= delta;
      nodes[edge.to].out_f -= delta;
      nodes[edge.from].in_f -= delta;
    }
  }

  void relabel(int v) {
    double mx = std::numeric_limits<double>::lowest();
    for (Edge& edge : G[v]) {
      if (residual_cap(edge) > 0) {
        mx = std::max(mx, nodes[edge.to].p - edge.cost - epsilon);
      }
    }
    nodes[v].p = mx;
  }

  void refine() {
    for (auto& edges : G) {
      for (Edge& edge : edges) {
        // if (edge.isrev) continue;
        if (reduced_cost(edge) >= 0) continue;
        if (residual_cap(edge) <= 0) continue;
        push(edge, residual_cap(edge));
      }
    }

    for (int i = 0; i < nodes.size(); i++) {
      if (is_active(i)) active_nodes.push(i);
    }

    while (!active_nodes.empty()) {
      int v = active_nodes.front();
      active_nodes.pop();
      if (!is_active(v)) continue;

      bool is_pushed = false;
      for (Edge& edge : G[v]) {
        if (reduced_cost(edge) >= 0) continue;
        if (residual_cap(edge) <= 0) continue;

        push(edge, std::min(residual_cap(edge), excess(v)));
        if (is_active(edge.from)) active_nodes.push(edge.from);
        if (is_active(edge.to)) active_nodes.push(edge.to);
        is_pushed = true;
        break;
      }

      if (!is_pushed) {
        relabel(v);
        if (is_active(v)) active_nodes.push(v);
      }
    }
  }

 public:
  CostScalingMinCostFlow(int N) : nodes(N), G(N), epsilon(0) {}

  void add_edge(int from, int to, int cap, int cost) {
    epsilon = std::max(epsilon, (double)abs(cost));
    G[from].emplace_back(from, to, cap, cost, G[to].size(), 0, false);
    G[to].emplace_back(to, from, cap, -cost, G[from].size() - 1, cap, true);
  }

  void set_b(int i, int b) { nodes[i].b = b; }

  long long mincostflow() {
    int N = nodes.size();
    while (epsilon >= 1.0 / N) {
      epsilon /= alpha;
      refine();
    }

    long long ret = 0;
    for (auto& edges : G) {
      for (Edge& edge : edges) {
        if (edge.isrev) continue;
        ret += edge.cost * edge.f;
      }
    }
    return ret;
  }
};
template<class F, class C>
class MinCostFlow {
  struct Edge {
    int rev, from, to;
    F cap, icap;
    C cost;
    Edge(int rev, int from, int to, F cap, C cost):
    rev(rev), from(from), to(to), cap(cap), icap(cap), cost(cost){}
  };

  int N;
  vector<vector<Edge>> G;
  const C INF;
public:
  MinCostFlow(int N):N(N),G(N),INF(numeric_limits<C>::max()){}

  void add_edge(int from, int to, F cap, C cost){
    G[from].emplace_back((int)(G[to].size()), from, to, cap, cost);
    G[to].emplace_back((int)(G[from].size()) - 1, to, from, 0, -cost);
  }
  
  C solve(int s, int t, F init_f){
    vector<C> dist(N);
    vector<int> prevv(N);
    vector<int> preve(N);

    C ret = 0;
    F f = init_f;
    while(f > 0){
      fill(dist.begin(), dist.end(), INF);
      dist[s] = 0;
      while(true){
        bool update = false;
        for(int v=0; v<G.size(); v++){
          if(dist[v] == INF) continue;
          for(int i=0; i<G[v].size(); i++){
            Edge& e = G[v][i];
            if(e.cap > 0 && dist[e.to] > dist[v] + e.cost) {
              dist[e.to] = dist[v] + e.cost;
              prevv[e.to] = v;
              preve[e.to] = i;
              update = true;
            }
          }
        }
        if(!update) break;
      }
      
      if(dist[t] == INF) return 0;
      
      F d = f;
      for(int v=t; v!=s; v=prevv[v]){
        d = min(d, G[prevv[v]][preve[v]].cap);
      }
      f -= d;
      ret += dist[t] * d;
      for(int v=t; v!=s; v=prevv[v]){
        Edge& e = G[prevv[v]][preve[v]];
        Edge& re = (e.from != e.to) ? G[e.to][e.rev] : G[e.to][e.rev+1];
        e.cap -= d;
        re.cap += d;
      }
    }
    return ret;
  }

  vector<int> get_selected_edges(int i){
    vector<int> ret;
    for(int j=0; j<G[i].size(); j++){
      Edge& e = G[i][j];
      if(e.cap == 0 && e.icap == 1) ret.push_back(e.to);
    }
    return ret;
  }  
};

int main(){
  int N;
  cin >> N;
  string S;
  cin >> S;
  vector<ll> v;
  rep(i,N){
    ll a;
    cin >> a;
    v.push_back(a);
  }

  Dinic dinic(N+2);
  MinCostFlow<ll,ll> mcf(N+2);
  //CostScalingMinCostFlow mcf(N+2);
  int s = N;
  int t = s+1;

  bool is_first = true;
  rep(i,N){
    if(is_first && S[i] == 'y'){
      mcf.add_edge(s, i, N, 0);
      dinic.add_edge(s, i, N);
      is_first = false;
    }
    if(S[i] == 'i'){
      mcf.add_edge(i, t, 1, -v[i]);
      dinic.add_edge(i, t, 1);
    }
    bool flg1 = true;
    bool flg2 = true;
    bool flg3 = true;
    bool flg4 = true;
    REP(j,i+1,N){
      if(flg1 && S[i] == S[j]){
        mcf.add_edge(i, j, N, 0);
        dinic.add_edge(i, j, N);
        flg1 = false;
      }
      if(flg2 && S[i] == 'y' && S[j] == 'u'){
        mcf.add_edge(i, j, 1, -v[i]);
        dinic.add_edge(i, j, 1);
        flg2 = false;
      }
      if(flg3 && S[i] == 'u' && S[j] == 'k'){
        mcf.add_edge(i, j, 1, -v[i]);
        dinic.add_edge(i, j, 1);
        flg3 = false;
      }
      if(flg4 && S[i] == 'k' && S[j] == 'i'){
        mcf.add_edge(i, j, 1, -v[i]);
        dinic.add_edge(i, j, 1);
        flg4 = false;
      }
    }
  }

  int f = dinic.max_flow(s, t);
  cerr << f << endl;
  //mcf.set_b(s, f);
  //mcf.set_b(t, -f);
  //cout << -mcf.mincostflow() << endl;
  cout << -mcf.solve(s, t, f) << endl;
  
  return 0;
}