# coding:utf-8
import sys


def int0(n):
    return int(n)-1


N=int(input())  # 街の数
C=int(input())  # 所持金
V=int(input())  # 道の数
S=list(map(int0, input().split()))  # S->T
T=list(map(int0, input().split()))  #
Y=list(map(int, input().split()))  # cost[S][T]
M=list(map(int, input().split()))  # time[S][T]

cost=[[C*V+1 for _ in range(N)] for _ in range(N)]
time=[[V*50+1 for _ in range(N)] for _ in range(N)]

for i in range(N):
    cost[i][i] = 0
    time[i][i] = 0

for i in range(V):
    cost[S[i]][T[i]]=Y[i]
    time[S[i]][T[i]]=M[i]


for i in range(N):
    for j in range(N):
        for k in range(N):
            cost[i][j]=min(cost[i][j], cost[i][k]+cost[k][j])

if cost[0][N-1]>C:
    print('-1')
    sys.exit(0)

for i in range(N):
    for j in range(i, N):
        for k in range(i, j):
            if cost[i][k]+cost[k][j]>C:
                continue
            time[i][j]=min(time[i][j], time[i][k]+time[k][j])

print(time[0][N-1])