#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
int main() {
char s[1005];
int k, a[30]={0}, ma=0, cnt=0;
scanf("%s", s);
scanf("%d", &k);
for(int i=0; i<26; i++) {
scanf("%d", &a[i]);
if(a[i]>ma) ma=a[i];
}
for(int i=0; i<strlen(s); i++) cnt+=a[s[i]-97]*(i+1);
for(int i=strlen(s)+1; i<=strlen(s)+k; i++) cnt+=ma*i;
printf("%d", cnt);
return 0;
}
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