#include <iostream>#include <vector>#include <algorithm>using namespace std;int main(){	vector<int> a(4);	cin >> a[0] >> a[1]>>a[2]>>a[3];	string str;	cin >> str;	int res = 0;	for(int i = 0 ; i < str.length(); ++ i) res+=a[str[i]-‘0‘-1];	cout<<res<<endl;	}