//vsp
#include<bits/stdc++.h>
#define cat(x) cerr << #x << " = " << x << "\n";
#define rep(i, a, b) for (int i = (a); i < (b); i++)
#define per(i, a, b) for (int i = (b) - 1; (a) <= i; i--)
#define FOR(i, n) for (int i = 0; i < (n); i++)
#define sz(x) int(x.size())
#define pb push_back
using ll = long long;
using namespace std;

const int N = 2e5;

int n, k, expo, prime, t[N], maks, cnt[26], cost[26];
string s;

ll solve(vector<int> v, int q = 0) {
	if (sz(v) == 1) {
		if (t[v[0]] == -1)
			return maks;
		else
			return cost[v[0]];
	}

	memset(cnt, 0, sizeof cnt);
	int c = 0;
	for (auto x : v) {
		if (t[x] != -1) {
			c++;
			cnt[t[x]]++;
		}
	}
	ll res = 0;
	rep(i, 0, 26)
		if (c == cnt[i]) {
			res = max(res, 1ll * cost[i] * sz(v) * (expo - q + 1));
		}
	ll res2 = 0;
	FOR(r, prime) {
		vector<int> new_v;
		for (int i = r; i < sz(v); i += prime)
			new_v.pb(v[i]);
		res2 += solve(new_v, q + 1);
	}
	return max(res, res2);
}

int main() {
	cin.tie(0)->sync_with_stdio(0);

	cin >> n >> s >> k;
	FOR(i, n) {
		if (s[i] == '?')
			t[i] = -1;
		else
			t[i] = s[i] - 'A';
	}

	FOR(i, k) {
		char c;
		cin >> c;
		int id = c - 'A';
		cin >> cost[id];
		maks = max(maks, cost[id]);
	}

	if (n == 1) {
		cout << solve({0}, 0) << '\n';
		return 0;
	}

	rep(i, 2, n + 1)
		if (n % i == 0) {
			prime = i;
			break;
		}

	vector<int> v(n);
	iota(v.begin(), v.end(), 0);

	int m = n;
	while (m % prime == 0) {
		m /= prime;
		expo++;
	}

	cout << solve(v, 0) << '\n';

	return 0;
}