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

const int N = 1e5 + 5;
int n, k, a[N], p, price[30], st, num[30];
long long dp[N][20][30];

int main() {
    ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    cin >>n;
    for (int i = 2; i <= n; ++i){
        if (n % i == 0){
            p = i;
            break;
        }
    }

    {
        st = 1;
        int s = p;
        while (s < n){
            s *= p;
            st++;
        }
    }

    {
        string s;
        cin >>s;
        cin >>k;
        for (int i = 1; i <= k; ++i){
            char x;
            cin >>x>>price[i];
            num[x - 'A'] = i;
        }

        for (int i = 1; i <= n; ++i){
            if (s[i - 1] == '?')a[i] = 0;else a[i] = num[s[i - 1] - 'A'];
            for (int j = 1; j <= k; ++j){
                if (a[i] == 0 || a[i] == j)dp[i][0][j] = price[j];
                if (a[i] != 0 && a[i] != j)dp[i][0][j] = -1;
                dp[i][0][0] = max(dp[i][0][0], dp[i][0][j]);
            }
        }
    }
    int m = n;
    int s = 1;
    for (int j = 1; j <= st; ++j){
        m /= p;
        s *= p;
        for (int i = 1; i <= m; ++i){
            for (int c = 1; c <= k; ++c){
                for (int l = i; l <= n; l += m){
                    if (dp[l][j - 1][c] == -1){
                        dp[i][j][c] = -1;
                        break;
                    }
                    dp[i][j][c] += dp[l][j - 1][c];
                }
                if (dp[i][j][c] != -1){
                    dp[i][j][c] += 1ll * price[c] * s;
                }
                //cout <<i<<" "<<j<<" "<<c<<" "<<dp[i][j][c]<<endl;
            }
            for (int l = i; l <= n; l += m){
                long long mx = 0;
                for (int c = 0; c <= k; ++c){
                    mx = max(mx, dp[l][j - 1][c]);
                }
                dp[i][j][0] += mx;
            }
            //cout <<i<<" "<<j<<" "<<0<<" "<<dp[i][j][0]<<endl;
            for (int c = 1; c <= k; ++c){
                dp[i][j][0] = max(dp[i][j][0], dp[i][j][c]);
            }
        }
    }
    cout <<dp[1][st][0];
}