### BUGGY CODE ###

'''input
3 5
1 2 1
2 3 0
'''
# connected components
from sys import stdin, setrecursionlimit
from bisect import bisect_left
import sys, resource

resource.setrlimit(resource.RLIMIT_STACK, [0x10000000, resource.RLIM_INFINITY])
sys.setrecursionlimit(0x100000)


def get_cost(m, h):
    if m == 'r':
        if h == 'p':
            return paper
    elif m == 's':
        if h == 'r':
            return rock
    else:
        if h == 's':
            return scissor
    return 0


def make(first, second):
    return str(first) + ' ' + str(second)


def brute(string, index, last, dp):
    if index == len(string):
        return 0
    x = -float('inf'); y = -float('inf'); z = -float('inf')
    if make(index, last) in dp:
        return dp[make(index, last)]
    if index != 0:
        if last != 'p':
            x = get_cost(string[index], 'p') + brute(string, index + 1, 'p', dp)
        if last != 's':
            y = get_cost(string[index], 's') + brute(string, index + 1, 's', dp)
        if last != 'r':
            z = get_cost(string[index], 'r') + brute(string, index + 1, 'r', dp)

    else:
        x = get_cost(string[index], 'p') + brute(string, index + 1, 'p', dp)
        y = get_cost(string[index], 's') + brute(string, index + 1, 's', dp)
        z = get_cost(string[index], 'r') + brute(string, index + 1, 'r', dp)
    dp[make(index, last)] = max(x, y, z)
    return max(x, y, z)

#
# def solve(string):
#     dp = [[0 for x in range(3)] for y in range(len(string))]
#     if string[0] == 'r':
#         dp[0] = [0, 0, paper]
#     elif string[0] == 's':
#         dp[0] = [rock, 0, 0]
#     else:
#         dp[0] = [0, scissor, 0]
#
#     for i in range(1, len(string)):
#         if string[i] == 'r':
#             dp[i][0] = max(dp[i - 1][1], dp[i - 1][2])
#             dp[i][1] = max(dp[i - 1][0], dp[i - 1][2])
#             dp[i][2] = max(dp[i - 1][0], dp[i - 1][1]) + paper
#         elif string[i] == 's':
#             dp[i][0] = max(dp[i - 1][1], dp[i - 1][2]) + rock
#             dp[i][1] = max(dp[i - 1][0], dp[i - 1][2])
#             dp[i][2] = max(dp[i - 1][0], dp[i - 1][1])
#         else:
#             dp[i][0] = max(dp[i - 1][1], dp[i - 1][2])
#             dp[i][1] = max(dp[i - 1][0], dp[i - 1][2]) + scissor
#             dp[i][2] = max(dp[i - 1][0], dp[i - 1][1])
#     # print(dp)
#     return max(dp[-1])

# main starts
n, k = list(map(int, stdin.readline().split()))
rock, scissor, paper = list(map(int, stdin.readline().split()))
string = stdin.readline().strip()
cost = 0
for i in range(k):
    temp = []
    j = i
    while j < n:
        temp.append(string[j])
        j += k
    dp = dict()
    cost += brute(temp, 0, '$', dp)
print(cost)

### FIXED CODE ###

'''input
3 5
1 2 1
2 3 0
'''
# connected components
from sys import stdin, setrecursionlimit
from bisect import bisect_left


def solve(string):
    dp = [[0 for x in range(3)] for y in range(len(string))]
    if string[0] == 'r':
        dp[0] = [0, 0, paper]
    elif string[0] == 's':
        dp[0] = [rock, 0, 0]
    else:
        dp[0] = [0, scissor, 0]

    for i in range(1, len(string)):
        if string[i] == 'r':
            dp[i][0] = max(dp[i - 1][1], dp[i - 1][2])
            dp[i][1] = max(dp[i - 1][0], dp[i - 1][2])
            dp[i][2] = max(dp[i - 1][0], dp[i - 1][1]) + paper
        elif string[i] == 's':
            dp[i][0] = max(dp[i - 1][1], dp[i - 1][2]) + rock
            dp[i][1] = max(dp[i - 1][0], dp[i - 1][2])
            dp[i][2] = max(dp[i - 1][0], dp[i - 1][1])
        else:
            dp[i][0] = max(dp[i - 1][1], dp[i - 1][2])
            dp[i][1] = max(dp[i - 1][0], dp[i - 1][2]) + scissor
            dp[i][2] = max(dp[i - 1][0], dp[i - 1][1])
    # print(dp)
    return max(dp[-1])

# main starts
n, k = list(map(int, stdin.readline().split()))
rock, scissor, paper = list(map(int, stdin.readline().split()))
string = stdin.readline().strip()
cost = 0
for i in range(k):
    temp = []
    j = i
    while j < n:
        temp.append(string[j])
        j += k
    cost += solve(temp)
print(cost)