#include <bits/stdc++.h>
using namespace std;

using ll = long long;
const int N = 1e4 + 10, R = 4.5e4 + 10;
// R=sqrt(2*10^9)
map<int, int> mp;
map<int, int> sp;
// 底数，指数
vector<int> pr;
bool ispr[R];
void prmake()
{
	memset(ispr, 1, sizeof(ispr));
	int i, j;
	for (i = 2; i < R; ++i)
	{
		if (ispr[i])
			pr.push_back(i);
		for (j = 0; j < pr.size() && pr[j] * i < R; ++j)
		{
			ispr[pr[j] * i] = false;
			if (i % pr[j] == 0)
				break;
		}
	}
}
void prdivide(int m, map<int, int> &p)
{
	int i, x;
	for (i = 0; i < pr.size(); ++i)
	{
		if (pr[i] > m)
			break;
		while (m % pr[i] == 0)
		{
			++p[pr[i]];
			m /= pr[i];
		}
	}
	if (m > 1)
		++pr[m];
}
bool check() // mp belong to p
{
	auto p1 = sp.begin(), p2 = mp.begin();
	while (p1 != sp.end())
	{
		if (p1->first > p2->first)
			return false;
		if (p1->first == p2->first)
			++p2;
		++p1;
	}
	return true;
}
ll gcd(ll a, ll b)
{
	if (a < b)
		swap(a, b);
	ll c;
	while (a % b != 0)
	{
		c = a % b;
		a = b;
		b = c;
	}
	return b;
}
#define lcm(a, b) (a * b / gcd(a, b))
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	int n, m1, m2, i, ans = INT_MAX, x;
	ll s;
	bool flag;
	cin >> n >> m1 >> m2;
	if (m1 == 1)
	{
		cout << "0\n";
		return 0;
	}
	prmake();
	prdivide(m1, mp);
	for (auto it = mp.begin(); it != mp.end(); ++it)
		it->second *= m2;
	for (i = 1; i <= n; ++i)
	{
		cin >> s;
		sp.clear();
		flag = true;
		x = INT_MIN;
		prdivide(s, sp);
		for (auto it = mp.begin(), it2 = sp.begin(); it != mp.end(); ++it)
		{
			while (it2->first != it->first)
			{
				if (it2->first > it->first)
				{
					flag = false;
					break;
				}
				++it2;
			}
			if (flag)
			{
				x = max(x, int(ceil(it->second / it2->second))); // x*sp[i]>=mp[i]
			}
			else
			{
				break;
			}
		}
		if (flag)
			ans = min(ans, x);
	}
	cout << (ans == INT_MAX ? -1 : ans) << '\n';
	return 0;
}