n,m,k=map(int,input().split())
c=list(map(int,input().split()))
a=list(map(int,input().split()))
y=[[] for i in range(m)]
for i in range(n):
  y[c[i]-1]+=[i]
ans=min(a)*k
for i in range(m):
  r=0
  for l in range(len(y[i])):
    while r+1<len(y[i]) and y[i][r+1]-y[i][l]+1<=k:
      r+=1
    ans=min(ans,(k-(r-l+1))*a[i])
print(ans)