# coding: utf-8
N = int(raw_input())
C = int(raw_input())
V = int(raw_input())
S = map(int, raw_input().split())
T = map(int, raw_input().split())
Y = map(int, raw_input().split())
M = map(int, raw_input().split())

INF = int(1e9+7)

# dpテーブル
# dp[i][k]=i番目の街で、使用金額k以下の時の最短経路
# 辿りつけない時はINF
dp = [[INF for _ in xrange(C+1)] for _ in xrange(N)]
dp[0][0]=0

toList = [[] for _ in xrange(N)]

for i in xrange(V):
	toList[S[i]-1].append((T[i]-1, Y[i], M[i]))

for i in xrange(N):
	for k in xrange(C+1):
		if dp[i][k]!=INF:
			for t, y, m in toList[i]:
				if k + y <= C:
					dp[t][k+y]=min(dp[t][k+y], dp[i][k]+m)

res = min(dp[N-1])
if res==INF: print -1
else: print res