#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
int len, a[1100], b[1100], m1, m2;

int check(int s) {
    if (len == 0) return 0;
    int ret = 0;
    for (int i = 1; i <= len; i++) {
        if (s % a[i] != 0) return inf;
        int t = 0; while (s % a[i] == 0) s /= a[i], t++;
        ret = max(ret, (b[i] * m2 + t - 1) / t);
    }
    return ret;
}

int main() {
    int n; scanf("%d", &n);
    scanf("%d%d", &m1, &m2);
    len = 0;
    for (int i = 2; i * i <= m1; i++) if (m1 % i == 0) {
        a[++len] = i;
        while (m1 % i == 0) {
            b[len]++;
            m1 /= i;
        }
    }
    if (m1 > 1) { a[++len] = m1; b[len] = 1; }
    int ans = inf;
    for (int i = 1; i <= n; i++) {
        int s; scanf("%d", &s);
        int t = check(s);
        ans = min(ans, t);
    }
    if (ans == inf) printf("-1\n"); else printf("%d\n", ans);
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
const int inf=0x3f3f3f3f;
int len,a[1100],b[1100],m1,m2;
int check(int s)
{
    if(len==0) return 0;
    int ret=0;
    for(int i=1;i<=len;i++)
    {
        if(s%a[i]!=0) return inf;
        int t=0;while(s%a[i]==0) s/=a[i],t++;
        ret=max(ret,(b[i]*m2+t-1)/t);
    }
    return ret;
}
int main()
{
    int n;scanf("%d",&n);
    scanf("%d%d",&m1,&m2);
    len=0;
    for(int i=2;i*i<=m1;i++)if(m1%i==0)
    {
        a[++len]=i;
        while(m1%i==0)
        {
            b[len]++;
            m1/=i;
        }
    }
    if(m1>1){a[++len]=m1;b[len]=1;}
    int ans=inf;
    for(int i=1;i<=n;i++)
    {
        int s;scanf("%d",&s);
        int t=check(s);
        ans=min(ans,t); 
    }
    if(ans==inf)printf("-1\n");else printf("%d\n",ans);
    return 0;
}