#include<bits/stdc++.h>
using namespace std;
#define test int t;scanf("%d", &t);while(t--)
#define sd(n) scanf("%d", &n)
#define loop(i, n) for(int i = 0;i<n;i++)
#define kloop(i, k, n) for(int i=k;i<n;i++)
#define rloop(i, n) for(int i = n;i>=0;i--)
#define rkloop(i, n, k) for(int i = n;i>=k;i--)
#define MOD 1000000007
#define PI 3.1415926535897932384626433832795
#define interactive(x) cout<<x<<"\n";fflush(stdout)
#define fil(name, val) memset(name, val, sizeof(name))
#define pb push_back
const int MAXN = 100005;
typedef long long ll;
/*int fact[MAXN];
int invfact[MAXN];
int inv(int a, int b){
    if(b==0)
        return 1;
    if(b&1)
        return (long long)a*inv(a, b-1)%MOD;
    else{
        int res = inv(a, b>>1);
        return (long long)res*res%MOD;
    }
}
void init(){
    fact[0] = 1;
    for(int i=1;i<MAXN;i++){
        fact[i] = (long long)fact[i-1]*i%MOD;
    }
    invfact[MAXN-1] = inv(fact[MAXN-1], MOD-2);
    for(int i=MAXN-1;i>0;i--){
        invfact[i-1] = (long long)invfact[i]*i%MOD;
    }
}
int C(int n, int r){
    if(r>n || r<0)
        return 0;
    return (long long)((long long)fact[n]*invfact[r]%MOD)*invfact[n-r]%MOD;
}
int gcd(int a, int b){
    while(a && b){
        if(a>b) a%=b;
        else b%=a;
    }
    return a+b;
}
ll lcm(int a, int b){
    ll A = (ll)a;
    ll B = (ll)b;
    return (A/gcd(a, b) * B);
}*/
int arr[26];
string s;
void solve(){
    loop(i, 26)sd(arr[i]);
    cin>>s;
    int ans = 1;
    loop(i, s.length())ans=max(ans, arr[s[i]-'a']);
    cout<<s.length()*ans;
}
int main(){
    solve();
    return 0;
}