import strutils, sequtils, future

const
  INF = 987654321

type
  Route = object
    to: int
    cost: int
    time: int
proc newRoute(): Route = Route(to: 0, cost: 0, time: 0)
proc newRoute(to, cost, time: int): Route = Route(to: to, cost: cost, time: time)

var
  N = stdin.readLine.parseInt
  C = stdin.readLine.parseInt
  V = stdin.readLine.parseInt
  S = stdin.readLine.split.map((x: string) => parseInt(x) - 1)
  T = stdin.readLine.split.map((x: string) => parseInt(x) - 1)
  Y = stdin.readLine.split.map(parseInt)
  M = stdin.readLine.split.map(parseInt)
  routes = newSeqWith(N, newSeqWith(0, newRoute()))
  dp = newSeqWith(N, newSeqWith(C+1, INF))

for i in 0.. <V:
  routes[S[i]].add(newRoute(T[i], Y[i], M[i]))

dp[0][0] = 0
for v in 0.. <N:
  for cost in 0.. C:
    for route in routes[v]:
      var ncost = cost + route.cost
      if ncost > C: continue
      dp[route.to][ncost] = min(dp[route.to][ncost], dp[v][cost] + route.time);

var res = min(dp[N-1])
if res == INF: res = -1
echo res