import sys
input = sys.stdin.readline
N, M, P = map(int, input().split())
a = list(map(int, input().split()))
a.sort()
x = 1
for i in range(40):
  if x > M:
    print(i)
    break

  for j in range(N - 1, -1, -1):
    if (x * a[j]) % P:
      x *= a[j]
      break
else:
  print(-1)