n, m, p = map(int, input().split())
A = list(map(int, input().split()))

from collections import defaultdict
C = defaultdict(lambda: 0)
D = []
for a in A:
    b = a
    cost = 1
    while a%p == 0:
        cost += 1
        a //= p
    C[cost] = max(C[cost], a)

M = max(A)

dp = [0]*101
dp[0] = 1
for c, a in C.items():
    for i in range(101):
        if i+c <= 100:
            dp[i+c] = max(dp[i+c], dp[i]*a)
ans = 10**18
for i, x in enumerate(dp):
    if x*M> m:
        ans = min(ans, i+1)
if ans != 10**18:
    print(ans)
else:
    print(-1)