#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
// https://github.com/JaroslavUrbann/ICPC-library

typedef long long ll;
typedef long double ld;

const int K=26;
int prices[K];
int mx=0;

ll solve(string s,int n,int p,int lg){
	ll res=0;
	char my=0;
	int same=1;
	for(int i=0;i<n;++i)if(s[i]!='?'){
		if(my&&my!=s[i])same=0;
		my=s[i];
	}
	if(same)res=(ll)(lg+1)*(my?prices[my-'A']:mx)*n;
	if(n==1){
		if(s[0]!='?')return prices[s[0]-'A'];
		return res;
	}
	vector<string>ns(p);
	for(int i=0;i<n;++i)ns[i%p]+=s[i];
	ll ors=0;
	for(int i=0;i<p;++i)ors+=solve(ns[i],n/p,p,lg-1);
	return max(res,ors);
}

void ProGamerMove(){
	int n;cin>>n;
	int p=1;
	for(int c=2;c<=n;++c)if(n%c==0){p=c;break;}
	int lg=0;
	int cn=n;
	while(cn!=1)++lg,cn/=p;
	string s;cin>>s;
	int k;cin>>k;
	for(int i=0;i<k;++i){
		char c;cin>>c;
		cin>>prices[c-'A'];
	}
	mx=*max_element(prices,prices+K);
	cout<<solve(s,n,p,lg)<<"\n";
}

signed main(){
	cin.tie(0)->sync_with_stdio(0);
	cin.exceptions(cin.failbit);
	cout<<setprecision(9)<<fixed;
	int tc=1;
	//cin>>tc;
	while(tc--)ProGamerMove();
}