n=int(input())
C=int(input())
e=[[] for i in range(n)]
m=int(input())
S=list(map(int,input().split()))
T=list(map(int,input().split()))
Y=list(map(int,input().split()))
M=list(map(int,input().split()))
for i in range(m):
  e[S[i]-1]+=[(T[i]-1,Y[i],M[i])]
X=10**10
q=[[X]*(C+1) for i in range(n)]
q[0][C]=0
for s in range(n-1):
  for c in range(C+1):
    if q[s][c]<X:
      for t,y,m in e[s]:
        if c-y>=0:
          q[t][c-y]=min(q[t][c-y],q[s][c]+m)
print(min(q[n-1]) if min(q[n-1])<X else -1)