using System;
using System.Collections.Generic;
using System.Linq;

namespace No1_2 {
    public class Program {

        public struct Input {
            public int Before { get; }
            public int After { get; }
            public int Cost { get; }
            public int Time { get; }

            public Input(int before, int t, int cost, int time) {
                Before = before;
                After = t;
                Cost = cost;
                Time = time;
            }
        }

        public struct Dp {
            public int Town { get; }
            public int Cost { get; }
            public int Time { get; }

            public Dp(int town, int cost, int time) {
                Town = town;
                Cost = cost;
                Time = time;
            }
        }

        public static void Main(string[] args) {
            var n = Read(Convert.ToInt32);//街の数
            var c = Read(Convert.ToInt32);//所持金
            var v = Read(Convert.ToInt32);//道の数
            var sn = ReadList(Convert.ToInt32);//街A
            var tn = ReadList(Convert.ToInt32);//街B
            var yn = ReadList(Convert.ToInt32);//街A → B へのコスト
            var mn = ReadList(Convert.ToInt32);//街A → B への時間

            var inputList = new List<Input>();
            for(var i = 0; i < v; i++) {
                inputList.Add(new Input(sn[i], tn[i], yn[i], mn[i]));
            }
            inputList.Sort((x, y) => x.After - y.After);

            var dpList = new List<Dp> { new Dp(1, 0, 0) };

            foreach(var linq in inputList.Select(input => (from dp in dpList
                where (dp.Town == input.Before) && (dp.Cost + input.Cost <= c)
                select new Dp(input.After, dp.Cost + input.Cost, dp.Time + input.Time)))){
                dpList.AddRange(linq.ToList());
            }

            var result = dpList.Where(dp => dp.Town == n).Select(reach => reach.Time).Concat(new[] {int.MaxValue}).Min();
            Console.WriteLine(result == int.MaxValue ? -1 : result);
        }

        public static TOutput Read<TOutput>(Converter<string, TOutput> converter) {
            return converter(Console.ReadLine());
        }

        public static List<TOutput> ReadList<TOutput>(Converter<string, TOutput> converter, char c = ' ') {
            return Console.ReadLine()?.Split(c).ToList().ConvertAll(converter);
        }
    }
}