#include<bits/stdc++.h>

using namespace std;

#define ll long long
#define fo(i,b,n) for(int i=(b); i<(n) ; i++)
#define xx first
#define yy second
#define pb push_back
#define sz(n) int(n.size())
#define pii pair
#define MP make_pair

#define read(x) scanf("%d",&x)
#define read2(x,y) scanf("%d%d",&x,&y)
#define readl(x) scanf("%lld",&x)
#define readl2(x,y) scanf("%lld%lld",&x,&y)
#define readd(x) scanf("%lf",&x)
#define readd2 scanf("%lf%lf",&x,&y)

#define pr(n) printf("%d",n)
#define prn(n) printf("%d\n",n)
#define prl(n) printf("%ld",n)
#define prln(n) printf("%ld\n",n)
#define prd(x) printf("%lf",x)
#define prdn(x) printf("%lf\n",x)

int a[30];

int main()
{
    fo(i,0,26)
    cin>>a[i];
    string s;
    cin>>s;
    int ans=-99999;
    fo(i,0,sz(s))
    {
        int temp=(int) (s[i]-'a');
        ans=max(ans,a[temp]);
    }

    cout<<ans*(sz(s))<<endl;
    return 0;
}