using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Text;
using System.Text.RegularExpressions;
using System.Linq;
using System.IO;

class Program
{
    static void Main(string[] args)
    {
        Magatro alice = new Magatro();
        alice.Scan();
        alice.Solve();
    }
}

public class Scanner
{
    private StreamReader Sr;
    private string[] S;
    private int Index;
    private const char Separator = ' ';
    public Scanner()
    {
        Index = 0;
        S = new string[0];
        Sr = new StreamReader(Console.OpenStandardInput());
    }
    private string[] Line()
    {
        return Sr.ReadLine().Split(Separator);
    }
    public string Next()
    {
        string result;
        if (Index >= S.Length)
        {
            S = Line();
            Index = 0;
        }
        result = S[Index];
        Index++;
        return result;
    }
    public int NextInt()
    {
        return int.Parse(Next());
    }
    public double NextDouble()
    {
        return double.Parse(Next());
    }
    public long NextLong()
    {
        return long.Parse(Next());
    }
    public decimal NextDecimal()
    {
        return decimal.Parse(Next());
    }
    public string[] StringArray(int index = 0)
    {
        Next();
        Index = S.Length;
        return S.Skip(index).ToArray();
    }
    public int[] IntArray(int index = 0)
    {
        return StringArray(index).Select(int.Parse).ToArray();
    }
    public long[] LongArray(int index = 0)
    {
        return StringArray(index).Select(long.Parse).ToArray();
    }
    public bool EndOfStream
    {
        get { return Sr.EndOfStream; }
    }
}

public class Magatro
{
    private int N, C, V;
    private int[] S, T, Y, M;

    int Infinity = int.MaxValue;

    //iの町からGraph[i].Tの町までYのコストで時間M
    private List<Road>[] Graph;

    //[現在の町の位置,かかるコスト]
    private int[,] Time;

    public void Scan()
    {
        Scanner sc = new Scanner();
        N = sc.NextInt();
        C = sc.NextInt();
        V = sc.NextInt();
        S = sc.IntArray();
        T = sc.IntArray();
        Y = sc.IntArray();
        M = sc.IntArray();
    }

    public void Solve()
    {
        InitGraph();
        InitTime();
        Calc();
        Write();
    }

    //S,T,Y,MをGraphに入れる
    private void InitGraph()
    {
        Graph = new List<Road>[N];

        for (int i = 0; i < N; i++)
        {
            Graph[i] = new List<Road>();
        }

        for (int i = 0; i < V; i++)
        {
            Graph[S[i]-1].Add(new Road(T[i] - 1, Y[i], M[i]));
        }
    }

    //Timeの値をInfinityにして初期化
    private void InitTime()
    {
        Time = new int[N, C + 1];

        for (int i = 0; i < N; i++)
        {
            for (int j = 0; j <= C; j++)
            {
                Time[i, j] = Infinity;
            }
        }
    }

    private void Calc()
    {
        Time[0, 0] = 0;

        for (int i = 0; i < N; i++)
        {
            for (int j = 0; j <= C; j++)
            {
                if (Time[i, j] != Infinity)
                {
                    foreach (Road r in Graph[i])
                    {
                        //コストがC以下なら
                        if (j + r.Y <= C)
                        {
                            //Timeを更新
                            Time[r.T, j + r.Y] = Math.Min(Time[r.T, j + r.Y], Time[i, j] + r.M);
                        }
                    }
                }
            }
        }
    }

    private void Write()
    {
        int anser = int.MaxValue;
        bool flag = false;

        for(int i = 0; i <= C; i++)
        {
            if (Time[N - 1, i] != Infinity)
            {
                //flagを立ててanserを更新
                anser = Math.Min(anser, Time[N - 1, i]);
                flag = true;
            }
        }

        if (flag)
        {
            Console.WriteLine(anser);
        }
        else
        {
            Console.WriteLine(-1);
        }
    }
}

struct Road
{
    public int T, Y, M;

    public Road(int t,int y,int m)
    {
        T = t;
        Y = y;
        M = m;
    }
}