### BUGGY CODE ###

import sys
from collections import deque
sys.setrecursionlimit(10**7)

input = sys.stdin.readline
N,K=map(int,input().rstrip().split())
R,S,P=map(int,input().rstrip().split())
T=list(input().rstrip())
TT=deque(T)

"""
2 1
10 10 10
ss
"""
#ans=0

def dfs(i,s):
 #   global ans
    ans=0
    
    
    if(len(s)>K):
        if(s[-K-1]==s[-1]):

            if(s[-1]=="r"):
                if(T[i-1]=="s"):
                    return -R
            if(s[-1]=="s"):
                if(T[i-1]=="p"):
                    return -S
            if(s[-1]=="p"):
                if(T[i-1]=="r"):
                    return -P


            return 0
    if(i==N):
        return 0
    t=T[i]


    if t=="r":
        ans=max(ans,dfs(i+1,s+"p")+P)
        ans=max(ans,dfs(i+1,s+"r"))
        ans=max(ans,dfs(i+1,s+"s"))
    
    if t=="s":
        ans=max(ans,dfs(i+1,s+"r")+R)
        ans=max(ans,dfs(i+1,s+"s"))
        ans=max(ans,dfs(i+1,s+"p"))
    if t=="p":
        ans=max(ans,dfs(i+1,s+"s")+S)
        ans=max(ans,dfs(i+1,s+"r"))
        ans=max(ans,dfs(i+1,s+"p"))
         
    return ans

def resolve():
    ans=dfs(0,"")
    print(ans)

import sys
from io import StringIO
import unittest

class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """5 2
8 7 6
rsrpr"""
        output = """27"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """7 1
100 10 1
ssssppr"""
        output = """211"""
        self.assertIO(input, output)
    def test_入力例_3(self):
        input = """30 5
325 234 123
rspsspspsrpspsppprpsprpssprpsr"""
        output = """4996"""
        self.assertIO(input, output)

if __name__ == "__main__":
    #unittest.main()
    resolve()

### FIXED CODE ###

import sys
from collections import deque


   
def resolve():
    
    input = sys.stdin.readline
    N,K=map(int,input().rstrip().split())
    R,S,P=map(int,input().rstrip().split())
    T=list(input().rstrip())

    ans=0
    flag=[0 for _ in range(N)]
    for i in range(N):
        if T[i]==T[i-K] and i>=K and flag[i-K]==True: #足さない条件、K個前が既に制約で足せなくなっていた時は、今回は足せるようになるのでflag管理
            continue
        if T[i]=="r":
            ans+=P
        if T[i]=="s":
            ans+=R
        if T[i]=="p":
            ans+=S
        flag[i]=True
    print(ans)

import sys
from io import StringIO
import unittest

class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """5 2
8 7 6
rsrpr"""
        output = """27"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """7 1
100 10 1
ssssppr"""
        output = """211"""
        self.assertIO(input, output)
    def test_入力例_3(self):
        input = """30 5
325 234 123
rspsspspsrpspsppprpsprpssprpsr"""
        output = """4996"""
        self.assertIO(input, output)

if __name__ == "__main__":
    #unittest.main()
    resolve()