using System.Collections;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

internal class Program
{
    private const long mod = 998244353;
    private const long mod17 = 1000000007;
    private const long INF = mod17 * mod17;
    
    public static void Main(string[] args)
    {
        var line = getar();
        int n = line[0], m = line[1], k = line[2];
        var c = getar();
        for (int i = 0; i < n; i++) c[i]--;
        var a = getar();
        long ans = INF;
        for (int i = 0; i < m; i++)
        {
            long val = (long)a[i] * k;
            ans = Math.Min(ans, val);
        }

        List<List<int>> ids = new List<List<int>>(m);
        for(int i=0;i<m;i++)ids.Add(new List<int>());
        for (int i = 0; i < n; i++)
        {
            ids[c[i]].Add(i);
        }

        for (int i = 0; i < m; i++)
        {
            if (ids[i].Count() == 0) continue;
            int r = 0;
            for (int l = 0; l < ids[i].Count(); l++)
            {
                while (r + 1 < ids[i].Count() && ids[i][r + 1] - ids[i][l] < k) r++;
                int num = r - l + 1;
                long val = (long)(k - num) * a[i];
                ans = Math.Min(ans, val);
            }
        }
        Console.WriteLine(ans);
    }
    public class lower_bound<T> : IComparer<T> where T : IComparable<T>
    {
        public int Compare(T x, T y)
        {
            return 0 <= x.CompareTo(y) ? 1 : -1;
        }
    }
    public static List<T> mkar<T>(int n, T val)
    {
        List<T> res = new List<T>(n);
        for(int i=0;i<n;i++)res.Add(val);
        return res;
    }

    public static int[] getar()
    {
        var res = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
        return res;
    }
}