#include <stdio.h>

static char S[100002];
static long long V[26];

static long long recurse(int s, int d, int p, int n, char ft, char mt) {
  if (d > n) return 0;
  char t = ft;
  for (int j = s; j < n; j += d) {
    if (t == '?') t = S[j];
    else if (S[j] != t && S[j] != '?') {
      t = 0;
      break;
    }
  }
  long long r1 = 0, r2 = 0;
  if (t) {
    if (t == '?') t = mt;
    r1 = V[t-'A'] * (n / d);
  }
  for (int j = 0; j < p; j++) {
    if (t) r1 += recurse(s + j * d, d * p, p, n, t, mt);
    r2 += recurse(s + j * d, d * p, p, n, ft, mt);
  }
  return (r1 > r2 ? r1 : r2);
}

int main() {
  int n = 0, k = 0, p = 2, mt = 'A';
  scanf("%d %s %d ", &n, S, &k);
  while ((k--) > 0) {
    char t = getchar();
    scanf("%lld ", &V[t-'A']);
    if (V[t-'A'] > V[mt-'A']) mt = t;
  }
  while (p < n && n % p != 0) p++;
  printf("%llu\n", recurse(0, 1, p, n, '?', mt));
  return 0;
}