package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"math"
	"os"
	"strconv"
)

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 1000005), 1000005)
	return scanner
}
func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}
func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}
func getNextInt64(scanner *bufio.Scanner) int64 {
	i, _ := strconv.ParseInt(getNextString(scanner), 10, 64)
	return i
}
func getNextUint64(scanner *bufio.Scanner) uint64 {
	i, _ := strconv.ParseUint(getNextString(scanner), 10, 64)
	return i
}
func getNextFloat64(scanner *bufio.Scanner) float64 {
	i, _ := strconv.ParseFloat(getNextString(scanner), 64)
	return i
}
func main() {
	fp := os.Stdin
	wfp := os.Stdout
	cnt := 0
	if os.Getenv("MASPY") == "ますピ" {
		fp, _ = os.Open(os.Getenv("BEET_THE_HARMONY_OF_PERFECT"))
		cnt = 2
	}
	if os.Getenv("MASPYPY") == "ますピッピ" {
		wfp, _ = os.Create(os.Getenv("NGTKANA_IS_GENIUS10"))
	}
	scanner := getScanner(fp)
	writer := bufio.NewWriter(wfp)
	solve(scanner, writer)
	for i := 0; i < cnt; i++ {
		fmt.Fprintln(writer, "-----------------------------------")
		solve(scanner, writer)
	}
	writer.Flush()
}
func solve(scanner *bufio.Scanner, writer *bufio.Writer) {
	n := getNextInt(scanner)
	c := getNextInt(scanner)
	v := getNextInt(scanner)
	ss := make([]int, v)
	tt := make([]int, v)
	yy := make([]int, v)
	mm := make([]int, v)
	for i := 0; i < v; i++ {
		ss[i] = getNextInt(scanner) - 1
	}
	for i := 0; i < v; i++ {
		tt[i] = getNextInt(scanner) - 1
	}
	for i := 0; i < v; i++ {
		yy[i] = getNextInt(scanner)
	}
	for i := 0; i < v; i++ {
		mm[i] = getNextInt(scanner)
	}
	g := newGraph(n)
	for i := 0; i < v; i++ {
		g.appendEdge(ss[i], tt[i], i, yy[i], mm[i])
		g.appendEdge(tt[i], ss[i], i, yy[i], mm[i])
	}
	for i := 0; i < n; i++ {
		g.v[i] = &vertex{
			ym: make([]int, c+1),
		}
		for j := 0; j < c+1; j++ {
			g.v[i].ym[j] = -1
		}
	}
	dd := &daikes{}
	heap.Init(dd)
	heap.Push(dd, newDaike(0, c, 0))
	for dd.Len() > 0 {
		p := heap.Pop(dd).(daike)
		if g.v[p.i].ym[p.y] != -1 {
			continue
		}
		g.v[p.i].ym[p.y] = p.m
		for _, e := range g.e[p.i] {
			if p.y-e.y < 0 {
				continue
			}
			if g.v[e.to].ym[p.y-e.y] == -1 {
				heap.Push(dd, newDaike(e.to, p.y-e.y, p.m+e.m))
			}
		}
	}

	ans := cint(math.MaxInt32)
	for i := 0; i < c+1; i++ {
		if g.v[n-1].ym[i] == -1 {
			continue
		}
		ans.min(cint(g.v[n-1].ym[i]))
	}
	if ans == cint(math.MaxInt32) {
		ans = -1
	}
	fmt.Fprintln(writer, ans)
}

type cint int

func (x *cint) min(y cint) *cint {
	if *x > y {
		*x = y
	}
	return x
}
func (x *cint) max(y cint) *cint {
	if *x < y {
		*x = y
	}
	return x
}
func newDaike(i, y, m int) daike {
	return daike{
		i: i,
		y: y,
		m: m,
	}
}

type daike struct {
	i, y, m int
}
type daikes []daike

func (h daikes) Len() int { return len(h) }
func (h daikes) Less(i, j int) bool {
	return h[i].m < h[j].m
}
func (h daikes) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
func (h *daikes) Push(x interface{}) {
	*h = append(*h, x.(daike))
}
func (h *daikes) Pop() interface{} {
	old := *h
	n := len(old)
	x := old[n-1]
	*h = old[0 : n-1]
	return x
}

type graph struct {
	v []*vertex
	e [][]*edge
}

func newGraph(n int) *graph {
	return &graph{
		v: make([]*vertex, n),
		e: make([][]*edge, n),
	}
}
func (g *graph) appendEdge(from, to, id, y, m int) {
	g.e[from] = append(g.e[from], &edge{
		to: to,
		id: id,
		y:  y,
		m:  m,
	})
}

type vertex struct {
	ym []int
}
type edge struct {
	to, id, y, m int
}