n, m, k = map(int, input().split())
C = list(map(int, input().split()))
A = list(map(int, input().split()))
for i in range(n):
    C[i] -= 1

ans = min(A) * k
inds = [[] for _ in range(m)]
for i, c in enumerate(C):
    inds[c].append(i)

for i, row in enumerate(inds):
    ma = 0
    l = 0
    for r in range(len(row)):
        while row[r] - row[l] >= k:
            l += 1

        ma = max(ma, r - l + 1)

    ans = min(ans, A[i] * (k - ma))

print(ans)