#include <bits/stdc++.h>
#include <chrono>
#include <ext/pb_ds/assoc_container.hpp>
#include <math.h>
using namespace __gnu_pbds;
using namespace std;
#define endl "\n"
#define mp make_pair
#define st first
#define nd second
#define pii pair<int, int>
#define pb push_back
#define _upgrade ios_base::sync_with_stdio(0), cout.setf(ios::fixed), cout.precision(10), cin.tie(0), cout.tie(0);
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define fwd(i, a, b) for (int i = (a); i < (b); ++i)
#define trav(a, x) for (auto &a : x)
#define all(c) (c).begin(), (c).end()
#define sz(X) (int)((X).size())
typedef long double ld;
typedef unsigned long long ull;
typedef long long ll;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> indexed_set; // find_by_order(x) <-returns x-th element   order_of_key(x) <- returns order of element x
// mt19937_64 gen(chrono::steady_clock::now().time_since_epoch().count());uniform_int_distribution<int> distr(0, 1e9);auto my_rand = bind(distr, gen); // my_rand() zwraca teraz liczbe z przedzialu [a, b]
#ifdef LOCAL
ostream &operator<<(ostream &out, string str) {
   for (char c : str)
      out << c;
   return out;
}
template <class L, class R> ostream &operator<<(ostream &out, pair<L, R> p) { return out << "(" << p.st << ", " << p.nd << ")"; }
template <class L, class R, class S> ostream &operator<<(ostream &out, tuple<L, R, S> p) {
   auto &[a, b, c] = p;
   return out << "(" << a << ", " << b << ", " << c << ")";
}
template <class T> auto operator<<(ostream &out, T a) -> decltype(a.begin(), out) {
   out << '{';
   for (auto it = a.begin(); it != a.end(); it = next(it))
      out << (it != a.begin() ? ", " : "") << *it;
   return out << '}';
}
void dump() { cerr << "\n"; }
template <class T, class... Ts> void dump(T a, Ts... x) {
   cerr << a << ", ";
   dump(x...);
}
#define debug(...) cerr << "[" #__VA_ARGS__ "]: ", dump(__VA_ARGS__)
#else
#define debug(...) 42
#endif

#define int long long

#define QU '?'

const int MAXC = 30;
const int MAXN = 1e5 + 99;
const int MAXL = 20;
const int inf = 1e12;

int tab[MAXC];
int dp[MAXL][MAXN][MAXC + 1];
string S;
int n;

int p = -1;

void clear() {
   rep(i, MAXC) tab[i] = -inf;
   rep(i, MAXL) rep(j, MAXN) rep(k, MAXC + 1) dp[i][j][k] = -inf;
}
int getidx(char c) { return c - 'A'; }

int getbest(int l, int n) {
   int r = -inf;
   rep(i, MAXC) r = max(r, dp[l][n][i]);
   return r;
}

void f() {
   rep(i, n) {
      if (S[i] == QU)
         rep(j, MAXC) dp[0][i][j] = tab[j];
      else
         dp[0][i][getidx(S[i])] = tab[getidx(S[i])];
      dp[0][i][MAXC] = getbest(0, i);
      debug(dp[0][i][MAXC]);
   }
}

void ssset(int t, int i, int d, int ile) {
   rep(j, MAXC + 1) {
      dp[t][i][j] = 0;

      rep(k, p) dp[t][i][j] += dp[t - 1][i + k * d][j];

      if (j != MAXC)
         dp[t][i][j] += ile * tab[j];

      if (dp[t][i][j] < 0)
         dp[t][i][j] = -inf;
   }

   dp[t][i][MAXC] = max(dp[t][i][MAXC], getbest(t, i));
   debug(t, i, dp[t][i][MAXC]);
}

int32_t main() {
   _upgrade;
   clear();

   cin >> n;
   cin >> S;
   debug(S, n);

   int m;
   cin >> m;

   rep(j, m) {
      char c;
      int x;
      cin >> c >> x;
      tab[getidx(c)] = x;
   }

   f();

   if (n == 1) {
      cout << dp[0][0][MAXC] << endl;
      exit(0);
   }

   for (int i = 2; i <= n; i++)
      if (n % i == 0) {
         p = i;
         break;
      }

   debug(p);

   n /= p;
   int ile = p;
   int t = 1;

   debug(n, ile, p);

   while (n > 0) {

      rep(i, n) ssset(t, i, n, ile);
      t++;
      n /= p;
      ile *= p;
   }

   cout << dp[t - 1][0][MAXC] << endl;
}