Black Square

#include<bits/stdc++.h>
#include<string>
using namespace std;

int main() 
{
    int a[4];
    for(int i=0;i<4;++i)
    {
        cin>>a[i];
    }
    string s;
    cin>>s;
    long long total=0;
    for(char c:s) 
    {
        int strip=c-'0';
        total=total+a[strip-1];
    }
    cout<<total<< endl;
    return 0;
}