#include <bits/stdc++.h>
using namespace std;
#define PB push_back
#define ZERO (1e-10)
#define INF int(1e9+1)
#define CL(A,I) (memset(A,I,sizeof(A)))
#define DEB printf("DEB!\n");
#define D(X) cout<<"  "<<#X": "<<X<<endl;
#define EQ(A,B) (A+ZERO>B&&A-ZERO<B)
typedef long long ll;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef pair<int,int> ii;
typedef vector<ii> vii;
#define IN(n) int n;scanf("%d",&n);
#define FOR(i, m, n) for (int i(m); i < n; i++)
#define F(n) FOR(i,0,n)
#define FF(n) FOR(j,0,n)
#define FT(m, n) FOR(k, m, n)
#define aa first
#define bb second
void ga(int N,int *A){F(N)scanf("%d",A+i);}
int N,L,P[256],a,b=1,p=-1,X;
char c,z[1<<20];
ll pw(ll a){
    ll I=0,S=1;
    while(S<N)S*=a,++I;
    return S^N?-1:I;
}
struct rt{ll c,x,N;}g;
rt dfs(int f,int s){
    if(s==N)return {z[f]^63?1<<(z[f]-65):0,z[f]^63?P[int(z[f])]:X,1};
    ll B=0,S=0,d=f,T=N/s,u;
    F(b)g=dfs(d,s*b),d+=s,S+=g.x,T+=g.N,B|=g.c;
    u=__builtin_popcount(B),g={B,u<2?u?max(S,T*P[64+__builtin_ffs(B)]):T*X:S,T};
    return g;
}
int main(void){
    scanf("%d%s%d",&N,z,&L);
    F(L)scanf(" %c%d",&c,&a),P[int(c)]=a;
    X=*max_element(P,P+256);
    while(!~p)p=pw(++b);
    printf("%lld\n",dfs(0,1).x);
    return 0;
}