#include<iostream>
#include<string>
#include<iomanip>
#include<algorithm>
#include<cmath>
#include<math.h>
using namespace std;
int main()
{
int a,b,c,d,s=0 ;
string x;
cin>>a>>b>>c>>d;
cin>>x;
for(int i=0;i<x.length();i++)
{
if(x[i]==1)
s+=a;
else if(x[i]==2)
s+=b;
else if (x[i]==3)
s+=c;
else if(x[i]==4)
s+=d;
}
cout<<s;
}
I2luY2x1ZGU8aW9zdHJlYW0+CiNpbmNsdWRlPHN0cmluZz4KI2luY2x1ZGU8aW9tYW5pcD4KI2luY2x1ZGU8YWxnb3JpdGhtPgojaW5jbHVkZTxjbWF0aD4KI2luY2x1ZGU8bWF0aC5oPgp1c2luZyBuYW1lc3BhY2Ugc3RkOwppbnQgbWFpbigpCgl7CglpbnQgICBhLGIsYyxkLHM9MCA7CglzdHJpbmcgeDsKCWNpbj4+YT4+Yj4+Yz4+ZDsKCWNpbj4+eDsKCWZvcihpbnQgaT0wO2k8eC5sZW5ndGgoKTtpKyspCgl7CgkJCgkJaWYoeFtpXT09MSkKCQkJcys9YTsKCQllbHNlIGlmKHhbaV09PTIpCgkJCXMrPWI7CgkJZWxzZSBpZiAoeFtpXT09MykKCQkJcys9YzsKCQllbHNlIGlmKHhbaV09PTQpIAoJCQlzKz1kOwoJfQoJY291dDw8czsKfQ==