#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
int n;
string s;
ll v[3030];
const string s0="yuki";
int main()
{
	cin>>n;
    cin>>s;
    for(int i=0; i<n; i++) cin>>v[i];
    ll ans=0;
    priority_queue<ll> que[3];
    for(int i=0; i<n; i++){
        if(s[i]=='y'){
            que[0].push(v[i]);
        }else if(s[i]=='u'){
            if(que[0].empty()) continue;
            ll x=que[0].top(); que[0].pop();
            que[1].push(x+v[i]);
        }else if(s[i]=='k'){
            if(que[1].empty()) continue;
            ll x=que[1].top(); que[1].pop();
            que[2].push(x+v[i]);
        }else{
            if(que[2].empty()) continue;
            ans+=que[2].top()+v[i];
            que[2].pop();
        }
    }
    cout<<ans<<endl;
	return 0;
}