using static System.Math;
using System;

public class Hello
{
    static void Main()
    {
        var n = int.Parse(Console.ReadLine().Trim());
        var s = Console.ReadLine().Trim();
        string[] line = Console.ReadLine().Trim().Split(' ');
        var a = Array.ConvertAll(line, int.Parse);
        getAns(n, s, a);
    }
    static void getAns(int n, string s, int[] a)
    {
        var b = new int[n];
        b[0] = s[0] == 'B' ? -a[0] : a[0];
        var tmax = b[0];
        var tmin = Min(0, b[0]);
        for (int i = 1; i < n; i++)
        {
            b[i] = s[i] == 'R' ? b[i - 1] + a[i] : b[i - 1] - a[i];
            tmax = Max(tmax, b[i]);
            tmin = Min(tmin, b[i]);
        }
        Console.WriteLine(Abs(tmax - tmin));
    }
}