using System;
using System.Collections.Generic;
using System.Linq;
using static System.Math;

namespace CSharp
{
    static class Program
    {
        static void Main(string[] args)
        {
            int n, k;
            ReadInt(out n, out k);
            int r, s, p;
            ReadInt(out r, out s, out p);
            var T = ReadString();

            int ans = 0;
            List<char> list = new List<char>();
            for (int i = 0; i < T.Length; i++)
            {
                char hand = Win(T[i]);
                if (i - k >= 0 && list[i - k] == hand)
                {
                    list.Add('\0');
                    continue;
                }

                switch (hand)
                {
                    case 'r':
                        ans += r;
                        break;
                    case 's':
                        ans += s;
                        break;
                    case 'p':
                        ans += p;
                        break;
                    default:
                        break;
                }

                list.Add(hand);
            }

            Console.WriteLine(ans);
        }

        static char Win(char hand)
        {
            switch (hand)
            {
                case 'r':
                    return 'p';
                case 's':
                    return 'r';
                case 'p':
                    return 's';
                default:
                    return '\0';
            }
        }

        #region Helpers

        static int[] ReadIntArray() => Console.ReadLine().Split().Select(s => int.Parse(s)).ToArray();
        static long[] ReadLongArray() => Console.ReadLine().Split().Select(s => long.Parse(s)).ToArray();

        static int[] ReadLineIntArray(int count) => Enumerable.Repeat(0, count).Select(_ => int.Parse(Console.ReadLine())).ToArray();
        static long[] ReadLineLongArray(int count) => Enumerable.Repeat(0, count).Select(_ => long.Parse(Console.ReadLine())).ToArray();

        static string ReadString() => Console.ReadLine();
        static int ReadInt() => int.Parse(Console.ReadLine());
        static long ReadLong() => long.Parse(Console.ReadLine());

        static void ReadInt(out int first)
        {
            var array = ReadIntArray();
            first = array[0];
        }

        static void ReadInt(out int first, out int second)
        {
            var array = ReadIntArray();
            first = array[0];
            second = array[1];
        }

        static void ReadInt(out int first, out int second, out int third)
        {
            var array = ReadIntArray();
            first = array[0];
            second = array[1];
            third = array[2];
        }

        static void ReadInt(out int first, out int second, out int third, out int fourth)
        {
            var array = ReadIntArray();
            first = array[0];
            second = array[1];
            third = array[2];
            fourth = array[3];
        }

        static void ReadLong(out long first)
        {
            var array = ReadLongArray();
            first = array[0];
        }

        static void ReadLong(out long first, out long second)
        {
            var array = ReadLongArray();
            first = array[0];
            second = array[1];
        }

        static void ReadLong(out long first, out long second, out long third)
        {
            var array = ReadLongArray();
            first = array[0];
            second = array[1];
            third = array[2];
        }

        static void ReadLong(out long first, out long second, out long third, out long fourth)
        {
            var array = ReadLongArray();
            first = array[0];
            second = array[1];
            third = array[2];
            fourth = array[3];
        }

        static string YesNo(bool condition) => condition ? "Yes" : "No";
        static string YESNO(bool condition) => condition ? "YES" : "NO";

        #endregion
    }
}

Measured memory_bytes: 14048