#include<bits/stdc++.h>
using namespace std;
using ll= long long ;
const ll M=2e6+10;
vector<ll>idx[22];
ll fa[M],n;
vector<ll>G[M];
ll p,k,dp[M][30],A[M],val[30];
ll tot,sz[M];
void build_tree(ll layer, ll nodeCnt) {
	if(nodeCnt==0)return ;
    idx[layer].resize(nodeCnt + 1);
    for (ll i = 1; i <= nodeCnt; i ++) idx[layer][i] = ++tot;
    if (layer) {
        for (ll i = 1; i <= nodeCnt; i ++) {
            for (ll j = i; j <= nodeCnt * p; j += nodeCnt) {
                fa[idx[layer - 1][j]] = idx[layer][i];
				G[idx[layer][i]].push_back(idx[layer-1][j]);
				//printf("%d -> %d\n",idx[layer][i],idx[layer-1][j]);
            }
        }
    }
    build_tree(layer + 1, nodeCnt / p);
}

void dfs(ll x){
	if(x<=n){
		if(A[x]){
			dp[x][A[x]]=val[A[x]];
			dp[x][0]=val[A[x]];
		}else{
			for(ll i=1;i<=26;++i){
				dp[x][i]=val[i];
				dp[x][0]=max(dp[x][0],val[i]);
			}
		}
		sz[x]=1;
	}else{
		for(ll y:G[x])dfs(y),sz[x]+=sz[y];
		for(ll i=0;i<=26;++i){
			bool fl=1;
			for(ll y:G[x]){
				dp[x][i]+=dp[y][i];
				if(dp[y][i]==0)fl=0;
			}
			if(fl)dp[x][i]+=sz[x]*val[i];
			else if(i)dp[x][i]=0;
		}
		for(ll i=0;i<=26;++i)
			dp[x][0]=max(dp[x][0],dp[x][i]);
	}
}
char s[M];
int  main(){
	scanf("%lld",&n);
	scanf("%s",s+1);
	for(ll i=1;i<=n;++i){
		if(s[i]>='A'&&s[i]<='Z')
			A[i]=s[i]-'A'+1;
	}
	scanf("%lld",&k);
	for(ll i=1;i<=k;++i){
		ll v;
		char op[10];
		scanf("%s %lld",op,&v);
		val[(*op)-'A'+1]=v;
	}
	if(n==1){
		if(A[1])printf("%lld",val[A[1]]);
		else {
			ll ans=0;
			for(int i=1;i<=26;++i)
				ans=max(ans,val[i]);
			printf("%lld",ans);
		}
		return 0;
	}
	for(ll i=2;i<=n;++i)
		if(n%i==0){
			p=i;
			break;
		}
	build_tree(0,n);	
	dfs(tot);
	printf("%lld\n",dp[tot][0]);
	return 0;
}