n, m, p = map(int, input().split())
a = list(map(int, input().split()))
mx = max(a)
t = (m + mx - 1) // mx
if t == 1:
    print(1)
    exit()
q = []
for ai in a:
    cnt = 1
    while ai % p == 0:
        cnt += 1
        ai //= p
    if ai == 1:
        continue
    q.append((ai, cnt))

dp = [0] * 100
dp[0] = 1
for i in range(50):
    for x, c in q:
        dp[i + c] = max(dp[i + c], dp[i] * x)
for i, v in enumerate(dp):
    if v >= t:
        print(i + 1)
        break
else:
    print(-1)