#ifdef LOCAL
    #define _GLIBCXX_DEBUG
    #define __clock__
#else
    #pragma GCC optimize("Ofast")
#endif
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using VI = vector<ll>;
using VV = vector<VI>;
using VS = vector<string>;
using PII = pair<ll, ll>;

// tourist set
template <typename A, typename B>
string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string& s) {
  return '"' + s + '"';
}

string to_string(const char* s) {
  return to_string((string) s);
}

string to_string(bool b) {
  return (b ? "true" : "false");
}

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cerr << '\n'; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
// tourist set end

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define rep(i,b) FOR(i, 0, b)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<'\n'
#define p2(s, t) cout << (s) << " " << (t) << '\n'
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << '\n'
#define p_yes() p("YES")
#define p_no() p("NO")
#define SZ(x) ((int)(x).size())
#define SORT(A) sort(ALL(A))
#define RSORT(A) sort(ALL(A), greater<ll>())
#define MP make_pair

void no(){p_no(); exit(0);}
void yes(){p_yes(); exit(0);}

const ll mod = 1e9 + 7;
const ll inf = 1e18;
const double PI = acos(-1);

ll dp[100010][3];

// j こっちのだした手
// rock scissors paper

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll N,K;
    cin >> N>>K;

    ll R,S,P;
    cin>>R>>S>>P;

    debug(N,K);
    debug(R,S,P);

    string s;cin>>s;

    if(s[0]=='r'){
      // paper
      dp[0][2] = P;
    }else if(s[0]=='s'){
      // rock
      dp[0][0] = R;
    }else{
      // scissors
      dp[0][1] = S;
    }

    FOR(i, 1, K){
      char c = s[i];
      // 過去のマックス
      ll ma = max({dp[i-1][0], dp[i-1][1], dp[i-1][2]});
      dp[i][0] = ma;
      dp[i][1] = ma;
      dp[i][2] = ma;

      if(c=='r'){
        // paper
        dp[i][2] += P;
      }
      else if(c=='s'){
        // rock
        dp[i][0] += R;
      }
      else{
        // scissors
        dp[i][1] += S;
      }
    }

    debug(dp[0][0]);
    debug(dp[0][1]);
    debug(dp[0][2]);

    
    debug(dp[1][0]);
    debug(dp[1][1]);
    debug(dp[1][2]);



    FOR(i, K, N){
      char c = s[i];
      // 過去のマックス
      ll ma = max({dp[i-1][0], dp[i-1][1], dp[i-1][2]});
      dp[i][0] = ma;
      dp[i][1] = ma;
      dp[i][2] = ma;

      // K手前が違う手なら普通に出せばいい
      if(c!=s[i-K]){
        if(c=='r'){
          // paper
          dp[i][2] += P;
        }
        else if(c=='s'){
          // rock
          dp[i][0] += R;
        }
        else{
          // scissors
          dp[i][1] += S;
        }
        continue;
      }

      // K前があいこでしのいだ？
      bool shinogi = false;
      if(dp[i-K][0]==dp[i-K][1] && dp[i-K][1]==dp[i-K][2]){
        shinogi = true;
      }
      debug(i, shinogi);
      debug(i-K);
      debug(dp[i-K][0]);
      debug(dp[i-K][1]);
      debug(dp[i-K][2]);

      if(!shinogi){
        // 今回はあいこでしのぐ
        debug(i, "shinogu");
        continue;
      }

      if(c=='r'){
        // paper
        dp[i][2] += P;
      }
      else if(c=='s'){
        // rock
        dp[i][0] += R;
      }
      else{
        // scissors
        dp[i][1] += S;
      }

      debug(i);
      debug(dp[i][0]);
      debug(dp[i][1]);
      debug(dp[i][2]);

    }

    ll ma = max({dp[N-1][0], dp[N-1][1], dp[N-1][2]});
    p(ma);
    
    return 0;
}

Measured memory_bytes: 2768