N, C, M = int(input()), int(input()), int(input())
U = list(map(int, input().split()))
V = list(map(int, input().split()))
Y = list(map(int, input().split()))
T = list(map(int, input().split()))
G = [[] for _ in range(N)]
for i in range(M):
    u, v = U[i]-1, V[i]-1
    G[u].append((v, Y[i], T[i]))

inf = 10 ** 18
dp = [[inf] * (C + 1) for _ in range(N)]
dp[0][0] = 0
for u in range(N-1):
    for v, y, t in G[u]:
        for c in range(C+1):
            if c + y <= C:
                dp[v][c + y] = min(dp[v][c + y], dp[u][c] + t)

ans = min(dp[-1])
print(ans if ans < inf else -1)