/* Akshit Chopra , BITS Pilani*/
#include <bits/stdc++.h>
using namespace std;
 
#define endl '\n'
#define spc ' '  
#define pi 2*acos(0.0) 
#define sqr(a) (((a) * (a)))
#define mpr make_pair
#define fi first
#define sc second
#define pb push_back
#define ffor(i,a,b) for( __typeof(b) i = a; i<=b ; ++i )
#define rfor(i,a,b) for( __typeof(b) i = a; i>=b ; --i )
#define min3(a,b,c) min(a,min(b,c))
#define max3(a,b,c) max(a,max(b,c))
#define count_one(a)    __builtin_popcountll(a)
#define isPower_2(a)      (((a)&&(a-1)) == 0)
#define sz(a)           (int)(a.size())
#define all(c)          (c).begin(),(c).end()
#define allr(c)         (c).rbegin(),(c).rend()
#define loop(c,i)       for(__typeof(c.begin()) i = c.begin(); i != c.end(); i++)
#define loopr(c,i)      for(__typeof(c.rbegin()) i = c.rbegin(); i != c.rend(); i++)
#define UNIQUE(a)       sort(all(a)), (a).erase(unique(all(a)),(a).end())
#define present(c,x)    ((c).find(x) != (c).end())
#define cpresent(c,x)   (find(all(c),x) != (c).end())
 
 
 
const int inf = 1e9;
 
typedef long long LL;
typedef vector<int> vi;
typedef vector<pair<int,int> >vpii;
typedef vector <LL> vll;
typedef vector <pair<LL,LL> > vpll;
typedef pair <int,int> pii;
typedef pair <LL,LL> pll;
 
void io()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cout.precision(15);
}
 
//Fast Reader
// template<class T>inline bool read(T &x){int c=getchar_unlocked();int sgn=1;while(~c&&c<'0'||c>'9'){if(c=='-')sgn=-1;c=getchar_unlocked();}for(x=0;~c&&'0'<=c&&c<='9';c=getchar_unlocked())x=x*10+c-'0'; x*=sgn; return ~c;}
double tick(){static clock_t oldt;clock_t newt=clock();double diff=1.0*(newt-oldt)/CLOCKS_PER_SEC;oldt = newt;return diff;} 
 
LL mulmod(LL a,LL b, LL m){LL q=(LL)(((long double)a*(long double)b)/(long double)m);LL r=a*b-q*m;if(r>m)r%=m;if(r<0)r+=m;return r;}/* for TOO LARGE mod of the order 10^18 etc */
 
template<typename T>T mod(T a,T b){while(a < 0)a+=b ;return a%b ;}
template <typename T>T power(T e, T n, T m){T x=1,p=e;while(n){if(n&1)x=mod(x*p, m);p=mod(p*p, m);n>>=1;}return x;}
template <typename T>T power(T e,T n){T x=1,p=e;while(n){if(n&1)x=x*p;p=p*p;n>>=1;}return x;}
template <typename T> T InverseEuler(T a, T m){return (a==1? 1 : power(a, m-2, m));}/*use IFF m is a prime number */
template<typename T>inline T gcd(T a, T b){T c;while (b){ c = b;b = a % b;a = c;}return a;}
template <typename T> T lcm(T a, T b){return (a*(b/gcd(a,b)));}
 
LL exEuclid(LL a,LL b,LL &x,LL &y)
{
    if(a == 0)
    {
        x = 0 ;
        y = 1 ;
        return b ;
    }
    if(b == 0)
    {
        x = 1 ;
        y = 0 ;
        return a ;
    }
    LL x1,y1 ;
    LL g = exEuclid(b%a , a , x1,y1) ;
    x = y1 - (b/a)*x1 ;
    y = x1 ;
    return g ; // return gcd of a,b ;
}
 
// #define MAX 50005
// #define mod 1000000009
// bool sv[MAX]  ;
// //vector<LL> primes ;
// void sieve()
// {
//     sv[1] = 1 ;
//     sv[2] = 0 ;
//     for(LL i=3;i<MAX;i+=2)
//     {
//         if(sv[i] == 0)
//         {
//             for(LL j=i*i;j<MAX;j += 2*i)
//             {
//                 if(sv[j] == 0) 
//                  sv[j] = 1 ;
//             }
//         }
//     }
//     primes.pb(2) ;
//     for(LL i=3;i<MAX;i+=2)
//     {
//         if(sv[i] == 0)li
//             primes.pb(i) ;
//     } 
// }
int h[28] ;
int main(int argc,char* argv[]) { 
    io() ;   
   // #ifndef ONLINE_JUDGE
     //   freopen("inp.txt", "r", stdin) ;
        // freopen("out.txt", "w", stdout);
    //#endif
    for(int i = 1 ; i <= 26 ; i++)
        cin >> h[i] ;
    string s ;
    cin >> s ;
    int ans = 0 ;
    for(int i = 0 ; i < s.length() ; i++){
        ans = max(ans , h[s[i] - 'a' + 1]) ;
    }
    ans = ans*s.length() ;
    cout << ans << endl;
    return 0 ;

}