#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
using namespace std;
long long m1[100] = {};
int main() {
    long long n, m, p;
    cin >> n >> m >> p;
    long long m2 = 0;
    for (int i = 0; i < n; i++) {
        long long a;
        cin >> a;
        long long co = 0;
        m2 = max(m2, a);
        while (a % p == 0) {
            a /= p;
            co++;
        }
        m1[co] = max(m1[co], a);
    }
    long long dp[4040] = {};
    dp[0] = 1;
    for (int i = 0; i < 4000; i++) {
        if (dp[i] * m2 > m) {
            cout << i+1 << endl;
            return 0;
        }
        for (int j = 0; j < 100; j++) {
            if (m1[j] == 0 || i + j + 1 > 4000) {
                continue;
            }
            dp[i + j + 1] = max(dp[i + j + 1], dp[i] * m1[j]);
        }
    }
    cout << "-1" << endl;
    return 0;
}