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

using ll = long long;
using pii = pair<int, int>;
template <class T>
using V = vector<T>;
template <class T>
using VV = V<V<T>>;

#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fi first
#define se second
#define rep(i, n) rep2(i, 0, n)
#define rep2(i, m, n) for (int i = m; i < (n); i++)
#define per(i, b) per2(i, 0, b)
#define per2(i, a, b) for (int i = int(b) - 1; i >= int(a); i--)
#define ALL(c) (c).begin(), (c).end()
#define SZ(x) ((int)(x).size())

constexpr ll TEN(int n) { return (n == 0) ? 1 : 10 * TEN(n - 1); }

template <class T, class U>
void chmin(T& t, const U& u) {
    if (t > u) t = u;
}
template <class T, class U>
void chmax(T& t, const U& u) {
    if (t < u) t = u;
}

template <class T, class U>
ostream& operator<<(ostream& os, const pair<T, U>& p) {
    os << "(" << p.first << "," << p.second << ")";
    return os;
}

template <class T>
ostream& operator<<(ostream& os, const vector<T>& v) {
    os << "{";
    rep(i, v.size()) {
        if (i) os << ",";
        os << v[i];
    }
    os << "}";
    return os;
}

#ifdef LOCAL
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << " " << H;
    debug_out(T...);
}
#define debug(...) \
    cerr << __LINE__ << " [" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#define dump(x) cerr << __LINE__ << " " << #x << " = " << (x) << endl
#else
#define debug(...) (void(0))
#define dump(x) (void(0))
#endif

const ll INF = TEN(9) + 10;
const int MX = 2000;

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int N, M, P;
    cin >> N >> M >> P;
    V<int> A(N), B(N), c(N);
    bool ok = 0;
    rep(i, N) {
        cin >> A[i];
        c[i] = 1;
        B[i] = A[i];
        while (A[i] % P == 0) {
            A[i] /= P;
            c[i]++;
        }
        if (A[i] != 1 || B[i] > M) {
            ok = 1;
        }
    }
    if (!ok) {
        cout << -1 << endl;
        return 0;
    }
    V<ll> dp(MX, -INF);
    dp[0] = 1;

    rep(i, MX) {
        if (dp[i] < 0) continue;
        if (dp[i] > M) {
            cout << i << endl;
            return 0;
        }
        rep(j, N) {
            if (dp[i] * B[j] > M) {
                cout << i + 1 << endl;
                return 0;
            }
            if (A[j] == 1) continue;

            ll nx = dp[i] * A[j];
            if (i + c[j] < MX) {
                chmax(dp[i + c[j]], nx);
            }
        }
    }

    return 0;
}