#include<iostream>
#include<algorithm>
#include<vector>

using namespace std;

int p, n;

bool translated(int i,int j) {
	int q = p;
	while (q <= n) {
		if (i % q != j % q)
			return i % q < j % q;
		q = q * p;
	}
	return false;
}

int translation[100100];

long long letter[200200][26];
long long best[200200];
long long any[200200];

char letterToCat[256];
long long value[26];

int main() {
	ios_base::sync_with_stdio(0);
	cin >> n;
	p = 2;
	while (n % p != 0 && p < n )
		p ++;
	for (int i = 0; i < n; i ++)
		translation[i] = i;
	sort(translation, translation + n, translated);
	string in;
	cin >> in;
	int letters;
	cin >> letters;
	char a;
	long long b;
	for (int i = 0; i < letters; i ++) {
		cin >> a >> b;
		letterToCat[a] = i;
		value[i] = b;
	}
	for (int i = 0; i < n; i ++) {
		int akt = (n - 1) / (p - 1) + translation[i];
		if (in[i] == '?') {
			any[akt] = 0; 
			best[akt] = 0; 
			for (int j = 0; j < letters; j ++) {
				letter[akt][j] = value[j];
				best[akt] = max(value[j], best[akt]);
			}
		}
		else {
			any[akt] = 0; 
			best[akt] = value[letterToCat[in[i]]]; 
			letter[akt][letterToCat[in[i]]] = value[letterToCat[in[i]]]; 
		}
	}
	int np = n;
	long long range = 1;
	while (1) {
		if (np == 1) 
			break;
		np = np / p;
		range = range * p;
		int this_start = (np - 1) / (p - 1);
		int next_start =  this_start + np;
		for (int x = 0; x < np; x ++) {
			int akt = this_start + x;
			long long akt_best = 0;
			for (int chosen = 0; chosen < letters; chosen ++) {
				long long pom = 0;
				bool ok = true;
				for (int i = 0; i < p; i ++) {
					if (letter[next_start + x * p + i][chosen] == 0){ 
						ok = false;
						break;
					}
					pom += letter[next_start + x * p + i][chosen];
				}
				if (!ok)
					continue;
				pom += range * value[chosen];
				letter[akt][chosen] = pom;
				if (pom > akt_best)
					akt_best = pom;
			}
			for (int i = 0; i < p; i ++)
				any[akt] += best[next_start + x * p + i];
			if (any[akt] > akt_best)
				akt_best = any[akt];	
			best[akt] = akt_best;
		}
	}
	cout << best[0];
}