#include <bits/stdc++.h>
using namespace std;
#define FOR(i,s,t) for(int i=(s),_t=(t); i<=_t; ++i)
#define DOR(i,s,t) for(int i=(s),_t=(t); i>=_t; --i)
typedef long long ll;
const int N=1e5+50;
string s;
ll val[N];
ll f[30][N];
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    cin >> s;
    int p=2;
    while(p<=n) {
        if(n%p==0) break;
        ++p;
    }
    int m;
    cin >> m;
    ll mx=0;
    FOR(i,1,m) {
        string s0;
        cin >> s0;
        cin >> val[s0[0]-'A'];
        mx=max(mx,val[s0[0]-'A']);
    }
    int q=n;
    int e=0;
    while(q) {
        FOR(i,0,q-1) {
            int c=-1;
            for(int j=i; j<n; j+=q) {
                if(s[j]!='?') {
                    if(c==-1) c=s[j]-'A';
                    else if(c!=s[j]-'A') {
                        c=-2;
                        break;
                    }
                }
            }
            ll v;
            if(c==-2) v=0;
            else if(c==-1) v=mx;
            else v=val[c];
            f[e][i]=v*(e+1)*n/q;
            if(e) {
                ll s=0;
                FOR(j,0,p-1) {
                    s+=f[e-1][j*q+i];
                }
                f[e][i]=max(f[e][i],s);
            }
        }
        e++;
        q/=p;
    }
    cout << f[e-1][0] << '\n';
    return 0;
}