#include <iostream>
#include <algorithm>
using namespace std ;
int n , a[41] , t[41] ;
long long kq = 0 , sum = 0 , s , p ;
void thu( int i )
{
if ( i == n + 1 ) return ;
for ( int j = t[i-1] + 1 ; j <= n ; j ++ ) {
t[i] = j ;
sum += a[j] ;
kq++ ;
if ( sum == s ) {
cout << kq * p << endl ;
exit(0) ;
}
if ( sum < s ) thu ( i + 1 ) ;
sum -= a[j] ;
kq-- ;
t[i] = 0 ;
if ( sum > s ) return ;
}
}
int main()
{
cin >> n >> s >> p ;
for ( int i = 1 ; i <= n ; i++ ) cin >> a[i] ;
sort ( 1 + a , 1 + n + a , greater <int> () ) ;
t[0] = 0 ;
thu ( 1 ) ;
cout << -1 ;
}
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