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 = [[301 for _ in range(N)] for _ in range(N)]
time = [[50*1001 for _ in range(N)] for _ in range(N)]
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):
            time[i][j] == min(time[i][j], time[i][j]+time[k][j])

ans = []
for j in range(N):
    if time[0][j] == 50050:
        continue
    ans.append(time[0][j])
print(max(ans))