n,m,p,*a = map(int,open(0).read().split())
t = [1]*n
m //= max(a)
for i in range(n):
    while a[i]%p==0:
        a[i] //= p
        t[i] += 1
dp = [1]*1024
for i in range(999):
    if dp[i] > m: break
    for ai,ti in zip(a,t):
        dp[i+ti] = max(dp[i+ti],dp[i]*ai)
else: i = -2
print(i+1)