#include <bits/stdc++.h>
#define FOR(i, a, n) for(ll i = (ll)a; i < (ll)n; i++)
#define FORR(i, n) for(ll i = (ll)n - 1LL; i >= 0LL; i--)
#define rep(i, n) FOR(i, 0, n)
#define ALL(x) begin(x), end(x)
using namespace std;
using ll = long long;
constexpr ll Mod = 998244353;
constexpr ll mod = 1e9 + 7;
constexpr ll inf = 1LL << 60;
const double PI = acos(-1);
template <typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {
    return a < b && (a = b, true);
}
template <typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {
    return a > b && (a = b, true);
}
/*-------------------------------------------*/

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    ll n, m, p;
    cin >> n >> m >> p;
    vector<ll> a(n), cnt(n, 1);

    rep(i, n) {
        cin >> a[i];
        while(a[i] % p == 0) {
            a[i] /= p;
            cnt[i]++;
        }
    }

    ll x = *max_element(ALL(a));
    if(x == 1) {
        cout << -1 << endl;
        return 0;
    }

    ll dp[5000]{1};

    rep(i, 5000) {
        if(dp[i] > m) {
            cout << i << endl;
            return 0;
        }
        rep(j, n) chmax(dp[i + cnt[j]], dp[i] * a[j]);
    }

    return 0;
}