#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

#define ll long long
#define lll __int128
#define ull unsigned long long
#define fi first
#define se second
#define db double
#define ld long double
#define lld __float128

/// order_of_key, find_by_order

template<class T, class COMP>
using custom_set = tree<T, null_type, COMP, rb_tree_tag, tree_order_statistics_node_update>;

template<class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

template<class T>
using ordered_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;

template<class T, class U>
using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rnd_64(chrono::steady_clock::now().time_since_epoch().count());

ll cst[27], mx;
vector<char> ctg;

ll dvd, pw, n;
string s;

ll rec(int vl, int i, int cr)
{
    bool good = 1;
    char c = '#';
    for(int j = i; j < n; j += vl)
    {
        if(s[j] != '?')
        {
            if(c == '#')
                c = s[j];
            else if(c != s[j])
            {
                good = 0; break;
            }
        }
    }
    if(!good)
    {
        ll sum = 0;
        for(int j = 0; j < dvd; j++)
        {
            sum += rec(vl*dvd, i+j*vl, cr+1);
        }
        return sum;
    }
    if(c == '#')
    {
        return (pw-cr+1) * mx*n/vl;
    }
    if(cr == pw)
    {
        return cst[c-'A'];
    }
    ll sum = 0;
    for(int j = 0; j < dvd; j++)
    {
        sum += rec(vl*dvd, i+j*vl, cr+1);
    }
    return max((pw-cr+1) * cst[c-'A']*n/vl, sum);
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    cin >> n;
    for(int i = 2; i <= n; i++)
    {
        if(n % i == 0)
        {
            dvd = i; break;
        }
    }
    int N = n;
    while(N > 1)
    {
        pw++; N /= dvd;
    }
    cin >> s;
    int k; cin >> k;
    for(int i = 0; i < k; i++)
    {
        char c; cin >> c;
        ctg.push_back(c);
        cin >> cst[c-'A'];
        mx = max(mx, cst[c-'A']);
    }
    cout << rec(1, 0, 0);
}






































/// shche ne vmerla Ykraina