def povtor(xs,numb,a=[]):
  i=0
  while i<numb:
    return povtorhelp(xs,numb,i+1,a+[xs[i]])
    i+=1

def povtorhelp(xs,numb,i,a=[]):
  if len(a) < numb:
    while i< numb:
      return povtorhelp(xs,numb,i+1,a+[xs[i]])
      i+=1
  else:
    return a