using System.IO;
using System.Collections.Generic;

namespace ConsoleApp2
{
    class Program
    {
        static void Main(string[] args)
        {
            var lines = File.ReadAllLines("input.txt");
            var marks = lines[1].Split(new[] { ' ', '\t', });
            var answers = lines[2];
            var marks_parsed = new List<int>();
            foreach(var mark in marks)
            {
                if(mark == "")
                {
                    continue;
                }
                marks_parsed.Add(int.Parse(mark));
            }
            int summary = 0;
            for (int i = 0; i < answers.Length; ++i)
            {
                if(answers[i] == '+')
                {
                    summary += marks_parsed[i];
                }
            }
            StreamWriter writer = new StreamWriter("output.txt");
            writer.Write(summary);
            writer.Close();
        }
    }
}