/* #pragma GCC optimize("O3,unroll-loops") */
/* #pragma GCC optimize("Ofast,unroll-loops") */
/* #pragma GCC target("avx2,popcnt") */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define pb push_back
#define mp make_pair
#define all(a) begin(a),end(a)
#define FOR(x,val,to) for(int x=(val);x<int((to));++x)
#define FORE(x,val,to) for(auto x=(val);x<=(to);++x)
#define FORR(x,arr) for(auto &x: arr)
#define FORS(x,plus,arr) for(auto x = begin(arr)+(plus); x != end(arr); ++x)
#define FORREV(x,plus,arr) for(auto x = (arr).rbegin()+(plus); x !=(arr).rend(); ++x)
#define REE(s_) {cout<<s_<<'\n';exit(0);}
#define GET(arr) for(auto &i: (arr)) sc(i)
#define whatis(x) cerr << #x << " is " << (x) << endl;
#define e1 first
#define e2 second
#define INF 0x7f7f7f7f
typedef std::pair<int,int> pi;
typedef std::vector<int> vi;
typedef std::vector<std::string> vs;
typedef int64_t ll;
typedef uint64_t ull;
#define umap unordered_map
#define uset unordered_set
using namespace std;
using namespace __gnu_pbds;
 
#ifdef ONLINE_JUDGE
#define whatis(x) ;
#endif
#ifdef _WIN32
#define getchar_unlocked() _getchar_nolock()
#define _CRT_DISABLE_PERFCRIT_LOCKS
#endif
template<class L, class R> ostream& operator<<(ostream &os, pair<L, R> P) { os<<"("<<P.first<<","<<P.second<<")"; return os; }
template<class L, class R> ostream& operator<<(ostream &os, map<L, R> P) { for(auto const &vv: P)os<<"("<<vv.first<<","<<vv.second<<")"; return os; }
template<class T> ostream& operator<<(ostream &os, set<T> V) { os<<"[";for(auto const &vv:V)os<<vv<<","; os<<"]"; return os; }
template<class T> ostream& operator<<(ostream &os, vector<T> V) { os<<"[";for(auto const &vv:V)os<<vv<<","; os<<"]"; return os; }
inline int fstoi(const string &str){auto it=str.begin();bool neg=0;int num=0;if(*it=='-')neg=1;else num=*it-'0';++it;while(it<str.end()) num=num*10+(*it++-'0');if(neg)num*=-1;return num;}
inline void getch(char &x){while(x = getchar_unlocked(), x < 33){;}}
inline void getstr(string &str){str.clear(); char cur;while(cur=getchar_unlocked(),cur<33){;}while(cur>32){str+=cur;cur=getchar_unlocked();}}
template<typename T> inline bool sc(T &num){ bool neg=0; int c; num=0; while(c=getchar_unlocked(),c<33){if(c == EOF) return false;} if(c=='-'){ neg=1; c=getchar_unlocked(); } for(;c>47;c=getchar_unlocked()) num=num*10+c-48; if(neg) num*=-1; return true;}template<typename T, typename ...Args> inline void sc(T &num, Args &...args){ bool neg=0; int c; num=0; while(c=getchar_unlocked(),c<33){;} if(c=='-'){ neg=1; c=getchar_unlocked(); } for(;c>47;c=getchar_unlocked()) num=num*10+c-48; if(neg) num*=-1; sc(args...); }
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; //s.find_by_order(), s.order_of_key() <- works like lower_bound
template<typename T> using ordered_map = tree<T, int, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define N 1000001

#define int ll

int cost[128];
int n;
string s;
int mostexp;
int basepow;
int deg;

/* void rec(int poz, int d){ */
/* int rec(int poz, int d){ */
int rec(int poz, int d, int crdeg){
    /* whatis(poz) */
    /* whatis(d) */
    /* whatis(crdeg) */
    int ret = 0;
    char wh = -1; // -1 none -2 > 1 dif.
    // -1 none 0 bad actually.
    for(int i = poz;;){
        /* if(s[i] == '?') */
        /*     continue; */
        if(s[i] != '?'){
            if(wh == -1)
                wh = s[i];
            else if(wh != s[i]){
                wh = 0;
                break;
            }
        }
        i += d;
        if(i >= n)
            i -= n;
        if(i == poz)
            break;
    }
    /* assert(wh != -1); */ // '?' actually.
    if(wh != 0){
        int whcost;
        if(wh == -1)
            whcost = mostexp;
        else
            whcost = cost[wh];
        /* ret = max(ret, whcost * d * (deg - crdeg + 1)); */
        ret = max(ret, whcost * (n / d) * (deg - crdeg + 1));
    }
    /* whatis("2nd") */
    // first basepow.
    // or is it?
    if(d != n){
        int oth = 0;
        int it = 0;
        for(int i = poz;;){
            oth += rec(i, d * basepow, crdeg + 1);
            if(++it == basepow)
                break;
            i += d;
            if(i >= n)
                i -= n;
            /* if(i == poz) */
            /*     break; */
        }
        ret = max(ret, oth);
    }
    /* whatis(poz) */
    /* whatis(d) */
    /* whatis(crdeg) */
    /* whatis(ret) */
    return ret;
}
 
/* int main(){ */
int32_t main(){
    ios_base::sync_with_stdio(0);cin.tie(0);
    sc(n);
    FORE(i,2,n){
        if(n % i == 0){
            basepow = i;
            int nn = n;
            deg = 0;
            while(nn != 1){
                nn /= basepow;
                ++deg;
            }
            break;
        }
        assert(0);
    }
    /* whatis(basepow) */
    /* whatis(deg) */
    getstr(s);
    int k;
    sc(k);
    FOR(x,0,k){
        char c;
        int wh;
        getch(c);
        sc(wh);
        cost[c] = wh;
        mostexp = max(mostexp, wh);
    }
    /* cout << rec(0, 1) << '\n'; */
    cout << rec(0, 1, 0) << '\n';
}