import sys
input = sys.stdin.readline
from collections import *

N, M, P = map(int, input().split())
A = list(map(int, input().split()))
Ma = max(A)
d = defaultdict(int)

for Ai in A:
    cost = 1
    
    while Ai%P==0:
        cost += 1
        Ai //= P
    
    d[cost] = max(d[cost], Ai)

dp = [0]*1000
dp[0] = 1

for i in range(1000):
    for k, v in d.items():
        if i+k<1000:
            dp[i+k] = max(dp[i+k], dp[i]*v)

for i in range(1000):
    if dp[i]*Ma>M:
        exit(print(i+1))

print(-1)