#include <bits/stdc++.h>

using namespace std;
ifstream fin ("dezastru.in");
ofstream fout("dezastru.out");
int sol[ 27 ] , m , n ;
double prod[ 27 ] , nr , s , a[ 27 ] , f[ 27 ] ;
void Back( int k )
{
  for( int i = 1 ;  i <= n ; i ++  )
    if( f[ i ] == 0 )
        {
         f[ i ] = 1 ;
         sol[ k ] =  i ;
         prod [ k ] = prod [ k - 1 ] * a [ i ] ;
         if( k == m )
            {
             cout<<prod[k]<<" ";
             s += prod [ k ] ;
             nr ++ ;
            }
         else
            Back( k + 1 );
         f[ i ] = 0 ;
        }
}
int main()
{
    int i;
    fin >> n >> m ;
    for ( i = 1 ; i <= n ; i ++)
        fin>> a[ i ];
    prod[ 0 ] = 1 ;
    Back( 1 );
    //cout<<nr<<" ";
    fout << s / nr ;
    return 0;
}