#include <bits/stdc++.h>
using namespace std;
using int128  = __int128_t;
using int64   = long long;
using int32   = int;
using uint128 = __uint128_t;
using uint64  = unsigned long long;
using uint32  = unsigned int;

#define ALL(obj) (obj).begin(),(obj).end()
template<class T> using priority_queue_reverse = priority_queue<T,vector<T>,greater<T>>;

constexpr int64 MOD = 1'000'000'000LL + 7; //'
constexpr int64 MOD2 = 998244353;
constexpr int64 HIGHINF = 1'000'000'000'000'000'000LL;
constexpr int64 LOWINF = 1'000'000'000'000'000LL; //'
constexpr long double PI = 3.1415926535897932384626433L;

template <class T> vector<T> multivector(size_t N,T init){return vector<T>(N,init);}
template <class... T> auto multivector(size_t N,T... t){return vector<decltype(multivector(t...))>(N,multivector(t...));}
template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}}
template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;}
template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const multiset<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const deque<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;}
template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;}
void print(void) {cout << endl;}
template <class Head> void print(Head&& head) {cout << head;print();}
template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);}
template <class T> void chmax(T& a, const T b){a=max(a,b);}
template <class T> void chmin(T& a, const T b){a=min(a,b);}
vector<string> split(const string &str, const char delemiter) {vector<string> res;stringstream ss(str);string buffer; while( getline(ss, buffer, delemiter) ) res.push_back(buffer); return res;}
inline constexpr int msb(int x) {return x?31-__builtin_clz(x):-1;}
inline constexpr int64 ceil_div(const int64 a,const int64 b) {return (a+(b-1))/b;}// return ceil(a/b)
void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;}
void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;}
void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;}

/*
 * @title Gcd - 高速GCD
 * @docs md/math/Gcd.md
 */
class Gcd{
public:
	inline static long long impl(long long n, long long m) {
		static constexpr long long K = 5;
		long long t,s;
		for(int i = 0; t = n - m, s = n - m * K, i < 80; ++i) {
			if(t<m){
				if(!t) return m;
				n = m, m = t;
			}
			else{
				if(!m) return t;
				n=t;
				if(t >= m * K) n = s;
			}
		}
		return impl(m, n % m);
	}
	inline static long long pre(long long n, long long m) {
		long long t;
		for(int i = 0; t = n - m, i < 4; ++i) {
			(t < m ? n=m,m=t : n=t);
			if(!m) return n;
		}
		return impl(n, m);
	}
	inline static long long gcd(long long n, long long m) {
		return (n>m ? pre(n,m) : pre(m,n));
	}
	inline static constexpr long long pureGcd(long long a, long long b) {
		return (b ? pureGcd(b, a % b):a);
	}
	inline static constexpr long long lcm(long long a, long long b) {
		return (a*b ? (a / gcd(a, b)*b): 0);
	}
	inline static constexpr long long extGcd(long long a, long long b, long long &x, long long &y) {
		if (b == 0) return x = 1, y = 0, a;
		long long d = extGcd(b, a%b, y, x);
		return y -= a / b * x, d;
	}
};

/*
 * @title Prime - 高速素因数分解・ミラーラビン素数判定
 * @docs md/math/Prime.md
 */
class Prime{
    using int128 = __int128_t;
    using int64  = long long;
    long long pow(long long x, long long n, long long mod) {
        long long res = 1;
        for (x %= mod; n > 0; n >>= 1, x=(int128(x)*x)%mod) if (n & 1) res = (int128(res)*x)%mod;
        return res;
    }
    int64 rho(int64 n){
        if(miller_rabin(n)) return n;
        if(n%2 == 0) return 2;
        for(int64 c=1,x=2,y=2,d;;c++){
            do{
                x=(int128(x)*x+c)%n;
                y=(int128(y)*y+c)%n;
                y=(int128(y)*y+c)%n;
                d=Gcd::gcd(x-y+n,n);
            }while(d==1);
            if(d<n) return d;
        }
    }
    vector<int64> factor(int64 n) {
        if(n <= 1) return {};
        int64 p = rho(n);
        if(p == n) return {p};
        auto l = factor(p);
        auto r = factor(n / p);
        copy(r.begin(), r.end(), back_inserter(l));
        return l;
    }
public:
    int miller_rabin(const int64 n) {
        if(n == 2) return 1;
        if(n < 2 || n%2 == 0) return 0;
        int64 m = n - 1;
        for (;!(m&1);m>>=1);
        for (int64 a: {2,325,9375,28178,450775,9780504,1795265022}) {
            if(a>=n) break;
            int64 x=m,r=pow(a,x,n);
            for(;x != n-1 && r != 1 && r != n-1;x <<= 1) r = (int128(r)*r)%n;
            if(r!=n-1 && x%2==0) return 0;
        }
        return 1;
    }
    vector<pair<int64,int64>> factorization(int64 n) {
        auto v = factor(n);
        vector<pair<int64,int64>> vp;
        sort(v.begin(),v.end());
        int64 prev = 0;
        for(int64 p:v) {
            if(p == prev) vp.back().second++;
            else vp.emplace_back(p,1);
            prev=p;
        }
        return vp;
    }
};

/**
 * @url 
 * @est
 */ 
int main() {
    cin.tie(0);ios::sync_with_stdio(false);
    int N; int64 M,P; cin >> N >> M >> P;
    vector<pair<int64,int64>> A,B;
    Prime pr;
    for(int i=0;i<N;++i) {
        int a;
        cin >> a;
        auto vp = pr.factorization(a);
        int64 cost = 1;
        for(auto& p:vp) if(p.first == P) cost += p.second;
        if(cost > 1) A.emplace_back(a,1);
        while(a%P==0) a /= P;
        if(a>1) B.emplace_back(a,cost);
    }
    int L = 1000;
    vector<int64> dp(L,0);
    dp[0]=1;
    // for(int i=0;i<L;++i) {
    //     for(auto p:B) {
    //         int64 a = p.first;
    //         int cost = p.second;
    //         int64 next = min(M+1,dp[i]*a);
    //         if(i+cost<L) {
    //             chmax(dp[i+cost],next);
    //         }
    //     }
    // }
    // for(int i=L-1;0<=i;--i) {
    //     for(auto p:A) {
    //         int64 a = p.first;
    //         int cost = p.second;
    //         int64 next = min(M+1,dp[i]*a);
    //         if(i+cost<L) {
    //             chmax(dp[i+cost],next);
    //         }
    //     }
    // }
    int ans = L;
    for(int i=0;i<L;++i) if(dp[i]>M) chmin(ans,i);
    if(ans == L) ans = -1;
    cout << ans << endl;
    return 0;
}