def eratosthenes_timing ( nmax ):

  from time import perf_counter

  L = list ( range ( 2, nmax + 1 ) )  
  P = []

  tic = perf_counter ( )      # Start the clock.

  while ( L != [] ):
    p = L[0]
    P.append ( p )
    for l in L:
      if ( l % p == 0 ):
        L.remove ( l )

  toc = perf_counter ( )     # Stop the clock.

  print ( 'eratosthenes ( ', nmax, ' ) required ', toc - tic, ' seconds' )
#
#  Here is how to reference the last element in a list:
#
  print ( '  Number of primes found was ', len ( P ) )
  print ( '  Biggest prime found was ', P[-1] )