1 #include <cstdio>
 2 #include <cmath>
 3 #include <cstdlib>
 4 #include <cstring>
 5 #include <string>
 6 #include <algorithm>
 7 #include <iostream>
 8 #include <iomanip>
 9 using namespace std ;
10
11 struct node{
12     int val,num,oth ;
13 };
14 const int inf = 2e9 ;
15 int m1,m2,n,tot,x,mi,mx,k,kk ;
16 node s[1001] ;
17
18 inline int read()
19 {
20     char ch = getchar() ;
21     int x = 0,f = 1 ;
22     while(ch<'0'||ch>'9') { if(ch=='-') f = -1 ; ch = getchar() ; }
23     while(ch>='0'&&ch<='9' ) { x = x*10 + ch - 48 ; ch = getchar() ; }
24     return x*f ;
25 }
26
27 int main()
28 {
29     n = read() ;
30     m1 = read() ;  m2 = read() ;
31     tot = 0 ;
32     if (m1==1) {cout<<0<<endl;return 0;}                   ///
33     for(int i=2,zz = int(sqrt(m1)) ;i<=zz;i++ )
34     {
35         if(m1%i==0)
36         {
37             s[++tot].val = i ;
38             while(m1%i==0) s[tot].num++,m1/=i ;
39             s[tot].num*=m2 ;
40         }
41     }
42     if(m1!=1) s[++tot].val = m1,s[tot].num = 1*m2 ;
43
44
45     mi = inf ;
46     for(int i=1;i<=n;i++)
47     {
48         x = read() ;
49         mx = 0 ;
50         for(int j=1;j<=tot;j++ )
51         {
52             s[ j ].oth = 0 ;
53             while(x%s[ j ].val==0) s[ j ].oth++,x/=s[ j ].val ;
54             if(s[ j ].oth==0) {
55                 mx = inf ;
56                 break ;
57             }
58             mx = max(mx,( s[ j ].num-1 ) /s[ j ].oth +1 ) ;
59         }
60         if(mx < mi )
61         {
62             mi = mx ;
63             k = i ; kk = x;
64         }
65     }
66     //printf("%d %d\n",k,kk) ;
67     if(mi != inf )
68         printf("%d\n",mi) ;
69     else
70         printf("-1\n") ;
71     return 0 ;
72 }