import java.util.Arrays;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;

public class Main
{
    private final static Main main = new Main();

    public static void main(String[] args)
    {
        long l = System.currentTimeMillis();
        main.answer();
        //System.out.println("処理時間：" + (System.currentTimeMillis() - l));
    }

    private void answer()
    {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int c = sc.nextInt();
        int v = sc.nextInt();
        sc.nextLine();
        String[] s = sc.nextLine().split(" ");
        String[] t = sc.nextLine().split(" ");
        String[] y = sc.nextLine().split(" ");
        String[] m = sc.nextLine().split(" ");
        sc.close();
        Data[][] map = new Data[n][n];
        for(int i=0; i<v; ++i)
        {
            int a = Integer.valueOf(s[i])-1;
            int b = Integer.valueOf(t[i])-1;
            int cost = Integer.valueOf(y[i]);
            int time = Integer.valueOf(m[i]);
            map[a][b] = new Data(i, cost, time);
        }
        System.out.println(new Dijkstra().dijkstra(map, c, n, n-1));
    }

    public class Dijkstra
    {
        private final int INF = Integer.MAX_VALUE/4;

        public int dijkstra(Data[][] map, int c, int n, int g)
        {
            int[] time = new int[n];
            Arrays.fill(time, INF);
            time[0] = 0;
            Queue<Data> queue = new LinkedList<Data>();
            queue.add(new Data(0, 0, 0));
            while(!queue.isEmpty())
            {
                Data d = queue.poll();
                int from = d.id;
                for(int to=0; to<n; ++to)
                {
                    if(map[from][to] != null && time[to] > time[from] + map[from][to].time && c >= d.cost + map[from][to].cost)
                    {
                        time[to] = time[from] + map[from][to].time;
                        queue.add(new Data(to, d.cost + map[from][to].cost, d.time));
                    }
                }
            }
            return time[g] == INF ? -1 : time[g];
        }
    }

    private class Data
    {
        private int id;
        private int cost;
        private int time;

        private Data(int id, int cost, int time)
        {
            this.id = id;
            this.cost = cost;
            this.time = time;
        }
    }
}