#include<bits/stdc++.h>
// #include<atcoder/all>
using namespace std;
// using namespace atcoder;
using lint = long long;
#define endl '\n'
lint const mod = 1e9+7;
//long const mod = 998244353;
map<lint,lint>dp;
lint maxx;

    lint n,m,p;
    lint a[200000];
    vector<vector<lint>>pa(200000);
lint search(lint x){
    if(x >= maxx)return 1;
    if(dp[x] != 0)return dp[x];

    lint tmp = 0;
    for(int i=0;i<n;i++){
        if(pa[i][0] > 1){
            tmp = max(tmp, search(x * pa[i][0]) + pa[i][1]);
        }
    }
    return dp[x] = tmp;

    
}

int main(){
    cin >> n >> m >> p;
    for(int i=0;i<n;i++)cin >> a[i];
    sort(a,a+n);
    maxx = ((m+1)/a[n-1]);
    while(maxx * a[n-1] <= m)maxx++;
    for(int i=0;i<n;i++){
        pa[i] = {a[i], 1};
        while(pa[i][0] % p == 0){
            pa[i][0] /= p;
            pa[i][1]++;
        }
    }
    bool chk = false;
    for(int i=0;i<n;i++){
        if(pa[i][0] > 1)chk = true;
    }
    if(!chk){
        cout << -1 << endl;
        return 0;
    }
    cout << search(1) << endl;
}