#include <bits/stdc++.h>

using namespace std;

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, a, b) for(int i = (a) - 1; i >= (b); i--)
#define SZ(a) int(a.size())
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef double db;

int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	
	int n;
	cin >> n;
	string s;
	cin >> s;
	
	map<char, int> value;
	int k;
	cin >> k;
	char mx = '0';
	FOR(i, 0, k)
	{
		char x;
		cin >> x;
		int val;
		cin >> val;
		
		value[x] = val;
		
		if(mx == '0' || val > value[mx])
			mx = x;
	}
	int m = n;
	int p = -1;
	for(int pr = 2; pr * pr <= n; pr++)
	{
		if(n % pr)
			continue;
		p = pr;
		n = 1;
		break;
	}
	if(n != 1)
		p = n;
	assert(p != -1);
	n = m;
	
	int beta = 0;
	int pw = 1;
	while(pw < n)
	{
		beta++;
		pw *= p;
	}
	
	vector<LL> dp(n);
	
	RFOR(alpha, beta + 1, 0)
	{
		vector<LL> ndp(pw);
		FOR(ost, 0, pw)
		{
			VI cnt(26, 0);
			int pos = ost;
			
			do{
				if(s[pos] != '?')
					cnt[s[pos] - 'A']++;
				
				pos += pw;
				if(pos >= n)
					pos -= n;
			}while(pos != ost);
			
			LL cur = 0;
			int num = 0;
			FOR(i, 0, 26)
			{
				if(cnt[i] != 0)
				{
					cur = value[char('A' + i)];
					num++;
				}
			}
			if(num == 0)
				cur = value[mx];
			if(num >= 2)
				cur = 0;
			
			//ndp[ost] = cur * (pwU - 1) / (p - 1);
			ndp[ost] = cur * (n / pw) * (beta + 1 - alpha);
			//cout << pw << " " << ost << " " << ndp[ost] << "\n";
			if(alpha != beta)
			{
				LL sum = 0;
				FOR(i, 0, p)
				{
					sum += dp[pw * i + ost];
				}
				ndp[ost] = max(ndp[ost], sum);
			}
		}
		
		dp = ndp;
		pw /= p;
	}
	cout << dp[0] << "\n";
		
		
	
	
	
	
	
	return 0;
}