#include <stdio.h>
#include <math.h>

int binom(int *x,int n,int k,int l,int h) {
  int m,kk,i=0 ;

  m=(l+h)/2 ;
  for (kk=0,i=0;i<n;i++)
    kk+=x[i]/m ;

  if (k==kk) return m ;
  if (kk<k) return binom(x,n,k,l,m) ;
              else return binom(x,n,k,m,h) ;
  
}

int solve1(int *x,int n,int k,int l,int h) 
{
  int m,mm ; int kk,i ;

  m=binom(x,n,k,l,h) ; 
  kk=k ;

  for (mm=m;;mm++) {
    for (kk=0,i=0;i<n;i++)
      kk+=x[i]/mm ;
    if (kk!=k) return m ;
    m=mm ;
  }
}


void solve(n,k) {
  int x[n],i ;
  double xx ;

  for (i=0;i<n;i++) {
    scanf("%lf ",&xx) ;
    x[i]=(int)(100.0*xx) ;
    /* printf("x[%d]=%d %f\n",i,x[i],xx) ; */
  }

  printf("%g\n",0.01*solve1(x,n,k,1,10000000)) ;

}



int main() {
  int n,k ;

  for(;;) {
    scanf("%d %d ",&n,&k) ;
    if (n==0 || k==0) break ;
    solve(n,k) ;
  }

  return 0 ;
}