#include <algorithm>
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <iostream>
#include <numeric>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <functional>
#include <iomanip>
using namespace std;
using ll = long long;

class range {private: struct I{int x;int operator*(){return x;}bool operator!=(I& lhs){return x<lhs.x;}void operator++(){++x;}};I i,n;
public:range(int n_):i({0}),n({n_}){}range(int i_,int n_):i({i_}),n({n_}){}I& begin(){return i;}I& end(){return n;}};

template<typename T, typename U> ostream& operator<<(ostream& os, const pair<T, U>& p){ return os << "{" << p.first << ", " << p.second << "}"; }
template<typename T> ostream& operator<<(ostream& os, const vector<T>& obj) { os << "{"; for (const auto& e : obj) os << e << ", "; return os << "}"; }
template<typename T> ostream& operator<<(ostream& os, const set<T>& obj) { os << "set{"; for (const auto& e : obj) os << e << ", "; return os << "}"; }
template<typename T, typename U> ostream& operator<<(ostream& os, const map<T, U>& obj) { os << "map{"; for (const auto& e : obj) os << e << ", "; return os << "}"; }
template<typename T> void take(vector<T>& vec, int n) { vec.resize(n); for (int i = 0; i < n; ++i) cin >> vec[i]; }

#ifdef ONLINE_JUDGE
#define dump(expr) ;
#else
#define dump(expr) { cerr << "\033[33m#L" << __LINE__ << ": " << expr << "\033[39m" << endl; }
#endif

namespace solver {

template<typename T1, typename T2> struct In2 {
  T1 a; T2 b;
  friend std::istream& operator>>(std::istream& is, In2& obj) { T1 t1; T2 t2; is >> t1 >> t2; obj = {t1, t2}; return is; }
};

template<typename T1, typename T2, typename T3> struct In3 {
  T1 a; T2 b; T3 c;
  friend std::istream& operator>>(std::istream& is, In3& obj) { T1 t1; T2 t2; T3 t3; is >> t1 >> t2 >> t3; obj = {t1, t2, t3}; return is; }
};

ll n, m, p;
vector<ll> vs;

void read() {
  cin >> n >> m >> p;
  take(vs, n);
}

template<typename T>
void vec_unique(vector<T>& v) {
  ranges::sort(v);
  auto result = ranges::unique(v);
  v.erase(result.begin(), result.end());
}

template <typename T> T chmin(T& a, T b) { return a = min(a, b); }
template <typename T> T chmax(T& a, T b) { return a = max(a, b); }

using RetType = ll;

RetType run() {
  vector<ll> kinds;
  for (ll d = 1; d * d <= m; ++d) {
    kinds.push_back(d);
    kinds.push_back(m / d);
  }
  vec_unique(kinds);
  vec_unique(vs);

  map<ll, ll> vals; // [cost] => max possible a[i]
  for (int i : range(n)) {
    ll a = vs[i];
    ll cost = 1;
    while (a % p == 0) a /= p, cost++;
    if (a == 1) continue;
    chmax(vals[cost], a);
  }

  map<ll, ll> dp;

  ll maxval = *ranges::max_element(vs);
  for (auto key : kinds) {
    if (key <= maxval) dp[key] = 1;
    else {
      dp[key] = 1000;
      for (auto it : vals) {
        chmin(dp[key], dp[key / it.second] + it.first);
      }
    }
  }

  return dp[m] < 1000 ? dp[m] : -1;
}

}  // namespace

template <typename F>
void run(F f) { if constexpr (std::is_same_v<decltype(f()), void>) f(); else cout << f() << endl; }

int main(int argc, char** argv) {
  cerr << fixed << setprecision(12);
  cout << fixed << setprecision(12);
  int testcase = 1;
  if (argc > 1) testcase = atoi(argv[1]);
  while (testcase--) {
    solver::read();
  }
  run(solver::run);
}