n,m,p = map(int,input().split())
*a, = map(int,input().split())

ma = max(a)
t = [1]*n
for i in range(n):
    while a[i]%p==0:
        a[i] //= p
        t[i] += 1

if all(ai==1 for ai in a) and ma <= m:
    print(-1)
    exit()

m = (m+ma)//ma
N = 1024
dp = [1]*N
for i in range(N):
    if dp[i] >= m: break
    for ai,ti in zip(a,t):
        if i+ti < N:
            dp[i+ti] = max(dp[i+ti],dp[i]*ai)
print(i+1)