#include <bits/stdc++.h>

#define ll long long

using namespace std;

int n, k;

string s;

ll mixed[33][123456];
ll pure[33][123456];
char type[33][123456];
bool que[33][123456];

int price[256];

int prime = 1, power = 0;

void print()
{
    for(int i = 0; i <= power; i++)
    {
        for(int j = 0; j < n; j++)
            cout << que[i][j] << " ";
        cout << endl;
    }
    cout << endl;
    for(int i = 0; i <= power; i++)
    {
        for(int j = 0; j < n; j++)
            cout << pure[i][j] << " ";
        cout << endl;
    }
    cout << endl;
    for(int i = 0; i <= power; i++)
    {
        for(int j = 0; j < n; j++)
            cout << mixed[i][j] << " ";
        cout << endl;
    }
    cout << endl;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n;
    cin >> s;
    cin >> k;

    char c;
    int a;
    ll ma = 0;
    char mac;
    for(int i = 0; i < k; i++)
    {
        cin >> c >> a;
        price[c] = a;
        if(a > ma)
        {
            ma = a;
            mac = c;
        }        
    }
    for(int i = 2; i <= n; i++)
    {
        if(n % i == 0)
        {
            prime = i;
            int nn = n;
            while(nn > 1)
            {
                power++;
                nn /= i;
            }
            break;
        }
    }

    for(int i = 0; i < n; i++)
    {
        if(s[i] != '?')
        {
            type[0][i] = s[i];
            pure[0][i] = price[s[i]];
            mixed[0][i] = price[s[i]];
            que[0][i] = false;
        }
        else
        {
            que[0][i] = true;
            mixed[0][i] = ma;
        }
    }

    int pw = prime;

    for(int e = 1; e <= power; e++)
    {
        for(int i = 0; i < n/pw; i++)
        {
            que[e][i] = true;
            mixed[e][i] = 0;
            bool types = false;
            for(int j = i; j < n; j += n/pw)
            {
                mixed[e][i] += mixed[e-1][j];
                que[e][i] &= que[e-i][j];
                if(type[e][i] && type[e-1][j] && type[e-1][j] != type[e][i])
                {
                    // cout << (int)type[e][i] << " " << (int)type[e-1][j] << endl;
                    types = true;
                }
                else if(!type[e][i] && type[e-1][j])
                {
                    type[e][i] = type[e-1][j];
                }
            }
            // cout << e << " " << i << " " << types << " " << type[e][i] << endl;
            if(!types)
            {
                if(type[e][i])
                {
                    pure[e][i] = (e + 1) * pw * price[type[e][i]];
                }
            }
            else
                pure[e][i] = 0;
            mixed[e][i] = max(mixed[e][i], pure[e][i]);
            if(que[e][i])
                mixed[e][i] = max(mixed[e][i], ma * pw * (e + 1));
        }
        pw *= prime;
    }
    // print();
    cout << mixed[power][0] << endl;
    return 0;
}