# 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*N+1 for a in range(N)] for b in range(N)]
time = [[1000*N+1 for c in range(N)] for d 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 k in range(N):
    for i in range(N):
        for j 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 k in range(N):
    for i in range(N):
        for j in range(N):
            # if cost[i][k]+cost[k][j]<=C:
            time[i][j] = min(time[i][j], time[i][k]+time[k][j])

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