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

typedef long long ll;

const int maxn=100000;
const ll INF=1e2;
ll n;
ll p,k;

ll a[maxn+50];
ll w[30];
ll dp[20][maxn+50][27];

void dfs(ll dep,ll u,ll len){
//	cerr << "dep,u,len : " << dep << " " << u << " " << len << endl;
	if (dep==0){
		if (a[u]==0){
			dp[dep][u][0]=-INF;
			for (int i=1;i<=26;i++) dp[dep][u][i]=w[i];	
		}
		else{
			for (int i=0;i<=26;i++) dp[dep][u][i]=-INF;
			dp[dep][u][a[u]]=w[a[u]];
		}
		/*
		cerr << "----------------" << endl;
		cerr << "check---- dep,u,len : " << dep << " " << u << " " << len << endl;
		for (int i=0;i<=3;i++){
			cerr << dp[dep][u][i] << " ";	
		}
		cerr << endl;
		cerr << "----------------" << endl;
		*/
		return;
	}
	
//	for (int i=0;i<=26;i++) dp[dep][u][i]=-INF;
	
	for (ll sel=0;sel<p;sel++){
		ll v=u+n/len*sel;
		dfs(dep-1,v,len/p);
		ll mx=-INF;
		for (int i=0;i<=26;i++){
			mx=max(mx,dp[dep][u][0]+dp[dep-1][v][i]);	
		}
		for (int i=0;i<=26;i++){
			mx=max(mx,dp[dep][u][i]+dp[dep-1][v][0]);	
		}
		vector<ll> lst(26+1+1);
		lst[0]=lst[27]=-INF;
		for (int i=1;i<=26;i++) lst[i]=dp[dep-1][v][i];
		
		vector<ll> pre(26+1+1);
		pre[0]=-INF;
		for (int i=1;i<=26;i++) pre[i]=max(pre[i-1],lst[i]);
		
		vector<ll> suf(26+1+1);
		pre[27]=-INF;
		for (int i=26;i>=1;i--) suf[i]=max(suf[i+1],lst[i]);
		
		for (int i=1;i<=26;i++){
			mx=max(mx,dp[dep][u][i]+max(pre[i-1],suf[i+1]));
		}
		
		dp[dep][u][0]=mx;
		for (int i=1;i<=26;i++){
			dp[dep][u][i]+=dp[dep-1][v][i];
		//	dp[dep][u][i]=max(dp[dep][u][i],-INF);
		}
	}
	for (int i=1;i<=26;i++) dp[dep][u][i]+=len*w[i];
	/*
	cerr << "----------------" << endl;
	cerr << "check---- dep,u,len : " << dep << " " << u << " " << len << endl;
	for (int i=0;i<=3;i++){
		cerr << dp[dep][u][i] << " ";	
	}
	cerr << endl;
	cerr << "----------------" << endl;
	*/
}

int main(){
	ios_base::sync_with_stdio(false);
	cin >> n;
	string str;
	cin >> str;
	for (int i=0;i<n;i++){
		if (str[i]=='?') a[i]=0;
		else a[i]=str[i]-'A'+1;	
	}
	
	{
		int Q;
		cin >> Q;
		for (;Q--;){
			char ch;
			ll v;
			cin >> ch >> v;
			w[ch-'A'+1]=v;
		}
	}
	
	for (p=2;p<=n;p++){
		k=0;
		ll now=1;
		while (now<n){
			now=now*p;
			k++;	
		}
		if (now==n) break;
	}
	
	dfs(k,0,n);
	
	ll ans=-INF;
	for (int i=0;i<=26;i++) ans=max(ans,dp[k][0][i]);
	cout << ans << "\n";
	return 0;
}