#include<bits/stdc++.h>
using namespace std;
#define ALL(x) begin(x),end(x)
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define mod 1000000007
using ll=long long;
const int INF=1000000000;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
// ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

struct IOSetup{
    IOSetup(){
        cin.tie(0);
        ios::sync_with_stdio(0);
        cout<<fixed<<setprecision(12);
    }
} iosetup;
 
template<typename T>
ostream &operator<<(ostream &os,const vector<T>&v){
    for(int i=0;i<(int)v.size();i++) os<<v[i]<<(i+1==(int)v.size()?"":" ");
    return os;
}
template<typename T>
istream &operator>>(istream &is,vector<T>&v){
    for(T &x:v)is>>x;
    return is;
}


signed main(){
    int n;ll m,p;cin>>n>>m>>p;
    vector<ll> v(60,-1);
    ll unko=0;
    rep(i,n){
        ll x;cin>>x;
        chmax(unko,x);
        ll t=0;
        while(x%p==0) x/=p,t++;
        if(x>1) chmax(v[t],x);
    }

    map<ll,ll> dp;
    dp[1]=0;

    rep(i,60)if(v[i]>0){
        for(auto s:dp){
            if(s.first<=m){
                if(!dp.count(s.first*v[i])){
                    if(s.first*v[i]>m) dp[s.first*v[i]]=s.second+1;
                    else dp[s.first*v[i]]=s.second+i+1;
                }
                else{
                    if(s.first*v[i]>m) chmin(dp[s.first*v[i]],s.second+1);
                    else chmin(dp[s.first*v[i]],s.second+i+1);
                }
            }
        }
    }

    ll res=LINF;
    for(auto s:dp){
        if(s.first>m) chmin(res,s.second);
        else if(s.first*unko>m) chmin(res,s.second+1);
    }
    if(res==LINF) cout<<-1<<endl;
    else cout<<res<<endl;
    return 0;
}