#include <bits/stdc++.h>
using namespace std;

const int N = 100100;
using ll = long long;

int n, p, m, k;
string str;

int value[30];

vector<ll> dp[30];
vector<int> col[30];
ll pw[30];

int merge(int x, int y) {
    if (x == 27 || y == 27) return 27;
    if (x == 26) return y;
    if (y == 26) return x;
    if (x == y) return x;
    return 27;
}

int main() {
    cin >> n >> str >> k;
    if (n > 1e5 || k > 26 || str.size() != n) {
        cout << "Fuck you";
        return 0;
    }
    for (int i = 0; i < k; i++) {
        string ch;
        int val;
        cin >> ch >> val;
        if (ch[0] < 'A' || ch[0] > 'Z') {
            cout << "Fuck you";
            return 0;
        }
        value[ch[0] - 'A'] = val;
        value[26] = max(value[26], val);
    }
    for (int i = 2; i <= n; i++) if (n % i == 0) { p = i; break; }
    if (n == 1) p = 2;

    for (int x = 1, i = 0; x <= n; x *= p, i++)
        pw[m = i] = x;
    

    if (pw[m] != n) {
        cout << "Fuck you";
        return 0;
    }

    for (int i = 0; i <= m; i++) {
        dp[i].resize(pw[i]);
        col[i].resize(pw[i]);
    }

    for (int i = 0; i < n; i++) {
        if (str[i] != '?' && (str[i] < 'A' || str[i] > 'Z')) {
            cout << "Fuck you";
            return 0;
        }
        col[m][i] = (str[i] == '?' ? 26 : str[i] - 'A');
        dp[m][i] = value[col[m][i]];
    }
    
    for (int i = m - 1; i >= 0; i--) {
        for (int j = 0; j < pw[i]; j++)
            col[i][j] = 26, dp[i][j] = 0;
        for (int j = 0; j < pw[i + 1]; j++) {
            col[i][j % pw[i]] = merge(col[i][j % pw[i]], col[i + 1][j]);
            dp[i][j % pw[i]] += dp[i + 1][j];
        }
        for (int j = 0; j < pw[i]; j++)
            dp[i][j] = max(dp[i][j], value[col[i][j]] * pw[m - i] * (m - i + 1));
    }
    cout << dp[0][0] << "\n";
    return 0;
}