Problem:
Score : 400 points

Problem Statement

At an arcade, Takahashi is playing a game called RPS Battle, which is played as follows:

The player plays N rounds of Rock Paper Scissors against the machine. (See Notes for the description of Rock Paper Scissors. A draw also counts as a round.)

Each time the player wins a round, depending on which hand he/she uses, he/she earns the following score (no points for a draw or a loss):

R points for winning with Rock;

S points for winning with Scissors;

P points for winning with Paper.

However, in the i-th round, the player cannot use the hand he/she used in the (i-K)-th round. (In the first K rounds, the player can use any hand.)

Before the start of the game, the machine decides the hand it will play in each round. With supernatural power, Takahashi managed to read all of those hands.

The information Takahashi obtained is given as a string T. If the i-th character of T (1 \leq i \leq N) is r, the machine will play Rock in the i-th round. Similarly, p and s stand for Paper and Scissors, respectively.

What is the maximum total score earned in the game by adequately choosing the hand to play in each round?

Notes

In this problem, Rock Paper Scissors can be thought of as a two-player game, in which each player simultaneously forms Rock, Paper, or Scissors with a hand.

If a player chooses Rock and the other chooses Scissors, the player choosing Rock wins;

if a player chooses Scissors and the other chooses Paper, the player choosing Scissors wins;

if a player chooses Paper and the other chooses Rock, the player choosing Paper wins;

if both players play the same hand, it is a draw.

Constraints

2 \leq N \leq 10^5

1 \leq K \leq N-1

1 \leq R,S,P \leq 10^4

N,K,R,S, and P are all integers.

|T| = N

T consists of r, p, and s.

Input

Input is given from Standard Input in the following format:

N K
R S P
T

Output

Print the maximum total score earned in the game.

Sample Input 1

5 2
8 7 6
rsrpr

Sample Output 1

27

The machine will play {Rock, Scissors, Rock, Paper, Rock}.

We can, for example, play {Paper, Rock, Rock, Scissors, Paper} against it to earn 27 points.
We cannot earn more points, so the answer is 27.

Sample Input 2

7 1
100 10 1
ssssppr

Sample Output 2

211

Sample Input 3

30 5
325 234 123
rspsspspsrpspsppprpsprpssprpsr

Sample Output 3

4996

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Linq;
using System.Collections.Generic;

namespace Contest
{
    partial class Program
    {
        static void Main(string[] args)
        {
            ABC149D();
        }

        static void ABC149A()
        {
            var st = ReadStrN();
            Console.WriteLine("{0}{1}", st[1], st[0]);
        }
        static void ABC149B()
        {
            var abk = ReadLongN();
            var A1 = Math.Max(0, abk[0] - abk[2]);
            var B1 = Math.Max(0, Math.Min(abk[1], abk[0] + abk[1] - abk[2]));
            Console.WriteLine("{0} {1}", A1, B1);
        }
        static void ABC149C()
        {
            var X = ReadInt();
            for(int i = X; i <= X * 2; ++i)
            {
                if (Util.IsPrime(i))
                {
                    Console.WriteLine(i);
                    return;
                }
            }
        }
        static void ABC149D()
        {
            var nk = ReadIntN();
            var rsp = ReadIntN();
            var str = ReadStr();
            var N = nk[0];
            var K = nk[1];
            var R = rsp[0];
            var S = rsp[1];
            var P = rsp[2];

            var dp = new int[N + 1, 3];
            for(int i = 0; i < N; ++i)
            {
                var c = str[i];
                dp[i + 1, 0] = (i + 1 >= K ? Math.Max(dp[i + 1 - K, 1], dp[i + 1 - K, 2]) : 0) + (c == 's' ? R : 0);
                dp[i + 1, 1] = (i + 1 >= K ? Math.Max(dp[i + 1 - K, 0], dp[i + 1 - K, 2]) : 0) + (c == 'p' ? S : 0);
                dp[i + 1, 2] = (i + 1 >= K ? Math.Max(dp[i + 1 - K, 0], dp[i + 1 - K, 1]) : 0) + (c == 'r' ? P : 0);
            }
            var result = Enumerable.Range(0, K).Select(i => Enumerable.Range(0, 3).Select(j => dp[N - i, j]).Max()).Sum();
            Console.WriteLine(result);
        }
        static void ABC149E()
        {
            var nm = ReadIntN();
            var A = ReadIntN();
            var N = nm[0];
            var M = nm[1];

            A = A.OrderBy(x => x).ToArray();
            Func<int, int> func = X => {
                int count = 0;
                int right = N;
                for (int left = 0; left < N; ++left)
                {
                    while (right > 0 && A[left] + A[right - 1] >= X)
                    {
                        right--;
                    }
                    count += (N - right);
                }
                return count;
            };

            int min = 1;
            int max = 200000;
            while (min + 1 < max)
            {
                var mid = (min + max) / 2;
                var count = func(mid);
                if (count < M)
                {
                    max = mid;
                }
                else
                {
                    min = mid;
                }
            }

            var ASum = new long[N + 1];
            for (int i = 0; i < N; ++i)
            {
                ASum[i + 1] = ASum[i] + A[i];
            }
            {
                var X = min;
                long sum = 0;
                int count = 0;
                int right = N;
                for (int left = 0; left < N; ++left)
                {
                    while (right > 0 && A[left] + A[right - 1] >= X)
                    {
                        right--;
                    }
                    count += (N - right);
                    sum += A[left] * (N - right) + ASum[N] - ASum[right];
                }
                sum -= (count - M) * X;
                Console.WriteLine(sum);
            }
        }

        class Util
        {
            public static readonly long P = 1000000007;

            public static long Sum(long[] array)
            {
                return Sum(array, array.Length);
            }
            public static long Sum(long[] array, int n)
            {
                long total = 0;
                for(int i = 0; i < n; ++i)
                {
                    total += array[i];
                }
                return total;
            }
            public static long Count(long[] array, long x)
            {
                return Count(array, x, array.Length);
            }
            public static long Count(long[] array, long x, int n)
            {
                long total = 0;
                for (int i = 0; i < n; ++i)
                {
                    total += (array[i] == x ? 1 : 0);
                }
                return total;
            }

            public static long GCD(long a, long b)
            {
                while (b > 0)
                {
                    var c = a % b;
                    a = b;
                    b = c;
                }
                return a;
            }
            public static bool IsPrime(long x)
            {
                var fact = Factorize(x);
                return fact.Count == 1 && fact.Values.ElementAt(0) == 1;
            }
            public static Dictionary<long,int> Factorize(long x)
            {
                var dict = new Dictionary<long, int>();
                long minp = 2;
                while (x > 1)
                {
                    bool ok = false;
                    for(long p = minp; p * p <= x; ++p)
                    {
                        if (x % p == 0)
                        {
                            if (!dict.ContainsKey(p))
                            {
                                dict.Add(p, 0);
                            }
                            dict[p]++;
                            minp = p;
                            x /= p;
                            ok = true;
                            break;
                        }
                    }
                    if (!ok)
                    {
                        if (!dict.ContainsKey(x)) { dict.Add(x, 0); }
                        dict[x]++;
                        break;
                    }
                }
                return dict;
            }
            public static long Inverse(long a, long p)
            {
                long b = p, c = 1, d = 0, e = 0, f = 0;
                while (b != 0)
                {
                    e = a / b;
                    f = b; b = a - e * b; a = f;
                    f = d; d = c - e * d; c = f;
                }
                c %= p;
                return c + (c < 0 ? p : 0);
            }
            public static long[] Facts(int n, long p)
            {
                var facts = new long[n + 1];
                facts[0] = 1;
                for (int i = 1; i <= n; ++i)
                {
                    facts[i] = (i * facts[i - 1]) % p;
                }
                return facts;
            }
            public static Func<int,int,long> Combin(int n, long P)
            {
                var fact = Facts(n, P);
                var inv = fact.Select(x => Inverse(x, P)).ToArray();
                return (N, M) =>
                {
                    if (N < 0 || N < M || M < 0) { return 0; }
                    return (((fact[N] * inv[M]) % P) * inv[N - M]) % P;
                };
            }

            /// <summary>
            /// Calc Combin(n,m) where n is large and m<=mMax
            /// </summary>
            public static Func<int,int,long> CombinLarge(int mMax, long p)
            {
                var inv = Enumerable.Range(0, mMax + 1).Select(x => Util.Inverse(x, Util.P)).ToArray();
                return (n, m) =>
                {
                    long mult = 1;
                    for (int i = 1; i <= m; ++i)
                    {
                        mult = (((mult * (n + 1 - i)) % Util.P) * inv[i]) % Util.P;
                    }
                    return mult;
                };
            }

            /// <summary>
            /// Calc 2^n mod p
            /// </summary>
            public static long Power2(long n, long p)
            {
                return Power(2, n, p);
            }
            public static long Power(long a, long n, long p)
            {
                long res = 1;
                long mult = a;
                for (int i = 0; i < 40; ++i)
                {
                    if ((n & ((long)1 << i)) > 0)
                    {
                        res = (res * mult) % p;
                    }
                    mult = (mult * mult) % p;
                }
                return res;
            }
        }
        class Geometric
        {
            /// <summary>
            /// 2点間の距離
            /// </summary>
            public static double Distance(Tuple<double, double> s, Tuple<double, double> t)
            {
                var diff1 = s.Item1 - t.Item1;
                var diff2 = s.Item2 - t.Item2;
                return Math.Sqrt(diff1 * diff1 + diff2 * diff2);
            }
            /// <summary>
            /// 2点の中点
            /// </summary>
            public static Tuple<double,double> Center(Tuple<double, double> s, Tuple<double, double> t)
            {
                return new Tuple<double, double>((s.Item1 + t.Item1) / 2, (s.Item2 + t.Item2) / 2);
            }

            /// <summary>
            /// 垂直二等分線 ax+by+c=0の係数(a,b,c)を出力
            /// </summary>
            public static Tuple<double,double,double> Bisector(Tuple<double, double> s, Tuple<double, double> t)
            {
                var a = t.Item1 - s.Item1;
                var b = t.Item2 - s.Item2;
                var c = -a * (s.Item1 + t.Item1) / 2 - b * (s.Item2 + t.Item2) / 2;
                return new Tuple<double, double, double>(a, b, c);
            }

            /// <summary>
            /// 2本の直線が平行か(絶対誤差Epsilon)
            /// </summary>
            public static bool IsParallel(Tuple<double, double, double> line1, Tuple<double, double, double> line2, double epsilon)
            {
                return Math.Abs(line1.Item1 * line2.Item2 - line1.Item2 * line2.Item1) < epsilon;
            }

            /// <summary>
            /// 2本の直線の交点(平行でないことを仮定)
            /// </summary>
            public static Tuple<double,double> Intersection(Tuple<double, double, double> line1, Tuple<double, double, double> line2)
            {
                var div = line1.Item1 * line2.Item2 - line1.Item2 * line2.Item1;
                var x = (line1.Item2 * line2.Item3 - line1.Item3 * line2.Item2) / div;
                var y = (line1.Item3 * line2.Item1 - line1.Item1 * line2.Item3) / div;
                return new Tuple<double, double>(x, y);
            }
        }

        struct MOD
        {
            public static long P = 1000000007;
            public readonly long V;

            public MOD(long a) { this.V = a; }
            public static implicit operator MOD(long a) { return new MOD(a); }
            public static MOD operator +(MOD a, MOD b) { return new MOD((a.V + b.V) % P); }
            public static MOD operator -(MOD a, MOD b) { return new MOD((a.V - b.V + P) % P); }
            public static MOD operator *(MOD a, MOD b) { return new MOD((a.V * b.V) % P); }
            public static MOD operator /(MOD a, MOD b) { return new MOD((a.V * b.Inverse().V) % P); }
            public MOD Inverse() { return Util.Inverse(V, P); }
            public MOD Power(long n) { return Util.Power(V, n, P); }
        }

        static string ReadStr()
        {
            return Console.ReadLine();
        }
        static string[] ReadStrN()
        {
            return Console.ReadLine().Split(' ');
        }
        static int ReadInt()
        {
            return Convert.ToInt32(Console.ReadLine());
        }
        static int[] ReadIntN()
        {
            return Console.ReadLine().Split(' ').Select(s => Convert.ToInt32(s)).ToArray();
        }
        static long ReadLong()
        {
            return Convert.ToInt64(Console.ReadLine());
        }
        static long[] ReadLongN()
        {
            return Console.ReadLine().Split(' ').Select(s => Convert.ToInt64(s)).ToArray();
        }
        static Tuple<string, string>[] ReadTupleStr(int n)
        {
            List<Tuple<string, string>> list = new List<Tuple<string, string>>();
            for (int i = 0; i < n; ++i)
            {
                var ab = ReadStrN();
                list.Add(new Tuple<string, string>(ab[0], ab[1]));
            }
            return list.ToArray();
        }
        static Tuple<long, long>[] ReadTupleLong(int n)
        {
            List<Tuple<long, long>> list = new List<Tuple<long, long>>();
            for (int i = 0; i < n; ++i)
            {
                var ab = ReadLongN();
                list.Add(new Tuple<long, long>(ab[0], ab[1]));
            }
            return list.ToArray();
        }
        static Tuple<double, double>[] ReadTupleDouble(int n)
        {
            List<Tuple<double, double>> list = new List<Tuple<double, double>>();
            for (int i = 0; i < n; ++i)
            {
                var ab = ReadLongN();
                list.Add(new Tuple<double, double>(ab[0], ab[1]));
            }
            return list.ToArray();
        }
    }
}