using Yorukatsu058.Questions;
using Yorukatsu058.Extensions;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace Yorukatsu058.Questions
{
    /// <summary>
    /// https://atcoder.jp/contests/abc149/tasks/abc149_d
    /// </summary>
    public class QuestionC : AtCoderQuestionBase
    {
        public override IEnumerable<object> Solve(TextReader inputStream)
        {
            var nk = inputStream.ReadIntArray();
            var round = nk[0];
            var restriction = nk[1];

            var rspPoint = inputStream.ReadIntArray();
            var enemyHands = inputStream.ReadLine().Select(GetHand).ToArray();
            var myHands = Enumerable.Repeat(Hand.None, round).ToArray();

            var point = 0;
            for (int r = 0; r < enemyHands.Length; r++)
            {
                var winnable = (Hand)(((int)enemyHands[r] + 2) % 3);
                if (r < restriction || myHands[r - restriction] != winnable)
                {
                    point += rspPoint[(int)winnable];
                    myHands[r] = winnable;
                }
            }

            yield return point;
        }

        enum Hand
        {
            None = -1,
            Rock = 0,
            Scissors = 1,
            Paper = 2
        }

        Hand GetHand(char c)
        {
            switch (c)
            {
                case 'r':
                    return Hand.Rock;
                case 's':
                    return Hand.Scissors;
                case 'p':
                    return Hand.Paper;
                default:
                    return Hand.None;
            }
        }
    }
}


namespace Yorukatsu058
{
    class Program
    {
        static void Main(string[] args)
        {
            IAtCoderQuestion question = new QuestionC();    // 問題に合わせて書き換え
            var answers = question.Solve(Console.In);
            foreach (var answer in answers)
            {
                Console.WriteLine(answer);
            }
        }
    }
}

#region Base Classes

namespace Yorukatsu058.Questions
{

    public interface IAtCoderQuestion
    {
        IEnumerable<object> Solve(string input);
        IEnumerable<object> Solve(TextReader inputStream);
    }

    public abstract class AtCoderQuestionBase : IAtCoderQuestion
    {
        public IEnumerable<object> Solve(string input)
        {
            var stream = new MemoryStream(Encoding.Unicode.GetBytes(input));
            var reader = new StreamReader(stream, Encoding.Unicode);

            return Solve(reader);
        }

        public abstract IEnumerable<object> Solve(TextReader inputStream);
    }

}

#endregion

#region Extensions

namespace Yorukatsu058.Extensions
{
    internal static class TextReaderExtensions
    {
        internal static int ReadInt(this TextReader reader) => int.Parse(ReadString(reader));
        internal static long ReadLong(this TextReader reader) => long.Parse(ReadString(reader));
        internal static double ReadDouble(this TextReader reader) => double.Parse(ReadString(reader));
        internal static string ReadString(this TextReader reader) => reader.ReadLine();

        internal static int[] ReadIntArray(this TextReader reader, char separator = ' ') => ReadStringArray(reader, separator).Select(int.Parse).ToArray();
        internal static long[] ReadLongArray(this TextReader reader, char separator = ' ') => ReadStringArray(reader, separator).Select(long.Parse).ToArray();
        internal static double[] ReadDoubleArray(this TextReader reader, char separator = ' ') => ReadStringArray(reader, separator).Select(double.Parse).ToArray();
        internal static string[] ReadStringArray(this TextReader reader, char separator = ' ') => reader.ReadLine().Split(separator);
    }
}

#endregion

Measured memory_bytes: 16480