#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#ifdef LOC
#include "debuglib.h"
#else
#define deb(...)
#define DBP(...)
#endif
using namespace std;
using   ll         = long long;
using   Vi         = vector<int>;
using   Pii        = pair<int, int>;
#define pb           push_back
#define mp           make_pair
#define x            first
#define y            second
#define rep(i, b, e) for (int i = (b); i < (e); i++)
#define each(a, x)   for (auto& a : (x))
#define all(x)       (x).begin(), (x).end()
#define sz(x)        int((x).size())

int uplg(int n) { return 32-__builtin_clz(n); }
int uplg(ll n)  { return 64-__builtin_clzll(n); }

ll money[26];
int p;

ll solve(const string& s) {
	int n = sz(s);

	int cnt[26] = {};
	each(c, s) if (c != '?') cnt[c-'A']++;

	int diff = 0;
	each(c, cnt) diff += c > 0;

	int depth = 1;
	for (int x = n; x > 1; x /= p) depth++;

	deb(s, diff);

	if (diff == 0) {
		return *max_element(money, money+26) * n * depth;
	}

	ll ans = 0;

	if (n > 1) {
		rep(i, 0, p) {
			string t;
			for (int j = i; j < n; j += p) t.pb(s[j]);
			ans += solve(t);
		}
	}

	if (diff == 1) {
		int j = 0;
		rep(i, 0, 26) if (cnt[i] > 0) j = i;
		ans = max(ans, money[j] * n * depth);
	}

	return ans;
}

int main() {
	cin.sync_with_stdio(0); cin.tie(0);
	cout << fixed << setprecision(18);

	int n; cin >> n;
	string s; cin >> s;

	int k; cin >> k;
	rep(i, 0, k) {
		string t;
		int m;
		cin >> t >> m;
		money[t[0]-'A'] = m;
	}

	for (p = 2; n%p != 0; p++);
	cout << solve(s) << '\n';
	return 0;
}