n, m, k = map(int, input().split())
c = [[] for _ in range(m)]
for i, x in enumerate(map(int, input().split())):
    c[x - 1].append(i)
ans = 10 ** 9 * k
for x, indices in zip(map(int, input().split()), c):
    j = 0
    for i in range(len(indices)):
        while j < len(indices) and indices[j] - indices[i] < k:
            j += 1
        ans = min(ans, (k - (j - i)) * x)

print(ans)