import sys
from operator import itemgetter
sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


N,M,P = MI()
A = LI()

max_A = max(A)
# 最後の1回の操作はmax_Aを掛ける
X = (M+max_A)//max_A  # 目標値

if X == 1:
    print(1)
    exit()

B = []
for a in A:
    r = 0
    while a % P == 0:
        r += 1
        a //= P
    B.append((r+1,-a))  # (操作回数,-(結局何倍になるか))

B = sorted(B,key=itemgetter(0,1))
C = []
r,a = B[0]
a *= -1
C.append((r,a))

for i in range(1,N):
    r,a = B[i]
    a *= -1
    if B[-1][0] < r and B[-1][1] < a:
        C.append((r,a))

for r,a in C:
    if a != 1:
        break
else:
    print(-1)
    exit()

dp = [1]*10000  # dp[i] = i回の操作でできる最大値
for i in range(1,10000):
    for r,a in C:
        if i >= r:
            dp[i] = max(dp[i],dp[i-r]*a)
    if dp[i] >= X:
        print(i+1)  # 最後の1回の操作を追加
        break