Vasya plays the LionAge II. He was bored of playing with a stupid computer, so he installed this popular MMORPG, to fight with his friends. Vasya came up with the name of his character — non-empty string s, consisting of a lowercase Latin letters. However, in order not to put up a front of friends, Vasya has decided to change no more than k letters of the character name so that the new name sounded as good as possible. Euphony of the line is defined as follows: for each pair of adjacent letters x and y (x immediately precedes y) the bonus c(x, y) is added to the result. Your task is to determine what the greatest Euphony can be obtained by changing at most k letters in the name of the Vasya's character.

Input

The first line contains character's name s and an integer number k (0 ≤ k ≤ 100). The length of the nonempty string s does not exceed 100. The second line contains an integer number n (0 ≤ n ≤ 676) — amount of pairs of letters, giving bonus to the euphony. The next n lines contain description of these pairs «x y c», which means that sequence xy gives bonus c (x, y — lowercase Latin letters,  - 1000 ≤ c ≤ 1000). It is guaranteed that no pair x y mentioned twice in the input data.

Output

Output the only number — maximum possible euphony оf the new character's name.

Examples

Input

winner 4
4
s e 7
o s 8
l o 13
o o 8


Output

36

Input

abcdef 1
5
a b -10
b c 5
c d 5
d e 5
e f 5


Output

20

Note

In the first example the most euphony name will be looser. It is easy to calculate that its euphony is 36.
#include <bits/stdc++.h>
#pragma GCC optimize "trapv"
long long int power(long long int x, long long int b) {
  long long int p = 1;
  while (b > 0) {
    if (b & 1) {
      p = p * x;
      p %= 998244353;
    }
    b >>= 1;
    x *= x;
    x %= 998244353;
  }
  return p % 998244353;
}
using namespace std;
struct ppp {
  char a;
  long long int b, c, d;
};
long long int N;
struct lex_compare {
  bool operator()(ppp p1, ppp p2) {
    if (p1.a == p2.a) {
      if (p1.b == p2.b)
        return p1.c < p2.c;
      else
        return p1.b < p2.b;
    } else {
      return p1.a < p2.a;
    }
  }
};
long long int n, m, k;
bool comp(pair<long long int, long long int> p1,
          pair<long long int, long long int> p2) {
  if (p1.first == p2.first)
    return p1.second < p2.second;
  else
    return p1.first < p2.first;
}
long long int score[26][26];
vector<vector<vector<long long int> > > dp(
    105, vector<vector<long long int> >(105, vector<long long int>(26, 1e15)));
long long int rec(long long int i, string &s, long long int kleft,
                  long long int currc) {
  if (kleft < 0) return INT_MIN;
  if (i >= s.size() - 1) {
    return 0;
  }
  if (dp[i][kleft][currc] != 1e15) return dp[i][kleft][currc];
  long long int ans = INT_MIN;
  {
    for (long long int j = 0; j < 26; j++) {
      long long int kreq = 0;
      if (s[i + 1] - 'a' != j) kreq++;
      ans = max(ans, score[currc][j] + rec(i + 1, s, kleft - kreq, j));
    }
  }
  return dp[i][kleft][currc] = ans;
  ;
}
int main() {
  string s;
  cin >> s;
  long long int k;
  cin >> k;
  memset(score, 0, sizeof(score));
  long long int n;
  cin >> n;
  ;
  for (long long int i = 0; i < n; i++) {
    char a, b;
    cin >> a >> b;
    long long int c;
    cin >> c;
    score[a - 'a'][b - 'a'] = c;
  }
  n = s.size();
  long long int ans = rec(0, s, k, s[0] - 'a');
  for (int i = 0; i < 26; i++) {
    if (i != s[0] - 'a') ans = max(ans, rec(0, s, k - 1, i));
  }
  cout << ans << "\n";
  return 0;
}
